China is stealing sensitive information from American computer networks and stepping up its online espionage, according to a US congressional panel.

Beijing's investment in rocket technology is also accelerating the militarisation of outer space and transforming it into the "commanding heights" of modern warfare, the advisory group claims. The strident warning, which may have a chilling effect on relations between the two Pacific powers, comes in the annual report of the US-China economic and security review commission due today.

A summary of the study, released in advance, alleges that networks and databases used by the US government and American defence contractors are regularly targeted by Chinese hackers. "China is stealing vast amounts of sensitive information from US computer networks," says Larry Wortzel, chairman of the commission set up by Congress in 2000 to investigate US-China issues.

The commission, consisting of six Democrats and six Republicans, says in its unanimous report that China's military modernisation and its "impressive but disturbing" space and computer warfare capabilities "suggest China is intent on expanding its sphere of control even at the expense of its Asian neighbors and the United States."

The commission recommends that the US upgrades its intelligence and homeland security systems which protect computer networks. It quotes the Chinese military strategist, Wang Huacheng, as describing US dependence on space assets and information technology as its "soft ribs".

China's space programme is "steadily increasing the vulnerability of US assets," the report says. Technical improvements in satellite imagery enables China to locate US aircraft carrier battle groups more accurately, faster and from farther away.

The People's Liberation Army officer and author Cai Fengzhen is quoted as saying that the "area above ground, airspace and outer space are inseparable and integrated. They are the strategic commanding height of modern informationalised warfare." "If this becomes Chinese policy," the report adds, "it could set the stage for conflict with the United States and other nations that expect the right of passage for their spacecraft."

Relations between China and the United States are businesslike and have not been under severe strain recently. During the presidential election campaign, Barack Obama said: "China is rising, and it's not going away," adding that Beijing was "neither our enemy nor our friend; they're competitors."

Allegations that Chinese hackers penetrate US defence computers have been made before, including reports of attacks on the Pentagon supposedly backed by the People's Liberation Army. US intelligence gave the assaults the codename "Titan Rain". In Britain last year Chinese cyberwarriors were said to have hacked into networks used by the Foreign Office, the House of Commons and other Whitehall departments.

China has said before that it is not trying to undermine other countries' interests and wishes to maintain good relations with the United States.

Thousands more jobs were axed today by some of Britain's leading companies, including Rolls-Royce, AstraZeneca and BAE Systems. In total, almost 4,000 posts are being cut from their global workforces, including about 600 in the UK.

In addition, French car manufacturer PSA Peugeot Citroen is cutting 2,700 jobs worldwide, although that is unlikely to effect British jobs. The company closed its remaining UK plant in Coventry two years ago with the loss of 2,300 jobs.

The biggest cutbacks are coming at engine-maker Rolls-Royce, which plans to make up to 2,000 workers redundant in response to the economic slowdown and delays to some of its most lucrative contracts.

It will axe "around 1,500 to 2,000" jobs from its 39,000-strong global workforce, or 4% of employees, including 140 cuts next year at its assembly and test facility in Derby. The reductions are in addition to the programme of 2,300 job losses the company announced in January, which is now nearly complete. Following the latest rounds of redundancies, the group will have reduced its workforce by about 10%.

Rolls-Royce is consulting with employee representatives about the job losses in Derby, its UK home for 100 years. It blamed delays on individual programmes, including the Airbus A380 and Boeing 787, for the cuts but also warned "economic uncertainties" meant it had to reduce its cost base.

The chief executive, Sir John Rose, said: "We are determined to maintain our focus on cost reduction and competitiveness as the world economy enters a challenging period. It is too early to determine the precise effects of the global economic downturn and programme delays. However, we wanted to give all our employees an early indication of the likely scale of the job reductions we expect in 2009."

The manufacturing union, Unite, described the news as "bitterly disappointing" and indicated it would fight any compulsory cuts, adding that the company risked being poorly prepared for a recovery when it came.

Unite's national officer Bernie Hamilton said: "Rolls-Royce must take a measured approach to this temporary downturn in the airline industry. In the past, the company has cut too many jobs and Rolls-Royce struggled to meet the upturn in the market.

"If there are to be redundancies in the UK, they must be voluntary. Unite will not accept any compulsory redundancies. Unite is urging the government to use the pre-budget report to support UK manufacturing and encourage companies to retain workers so a skill shortage is not the outcome when market conditions improve. We have a world-class aerospace industry. We must retain these highly skilled jobs at all costs."

The company said it hoped to keep compulsory redundancies to a minimum by laying off temporary staff and by not replacing staff who retire. Rolls-Royce said it was too early to say where the axe would fall. It has staff in more than 50 countries, although 60% of its workforce - about 22,100 people - are in the UK.

Pharmaceuticals giant AstraZeneca announced 1,400 job cuts today with the closure of three sites in Spain, Belgium and Sweden by 2013. That is expected to lead to about 250 job losses over the next five years at its plant in Macclesfield, Cheshire, where 3,000 people are employed. Separately, the company said it was investing in its manufacturing and packaging plant in China.

Defence company BAE is to axe 200 jobs in the UK, citing cuts in goverment spending on the armed forces. It said the Minsitry of Defence was spending less on its armoured fighting vehicles programme, leading to job losses in its land system business which will affect plants at Newcastle, Leeds, Barrow, Telford and Leicester. The company has launched a voluntary redundancy programme.

PSA Peugeot Citroen said it was cutting jobs from its workforce of 200,000 in response to falling European car sales, which it said have plummeted by 17% since July. It warned that "this recession will continue in 2009" and predicted car sales in Europe would be down by at least 10% this year.

Several international media groups have sent a letter of protest to Israel's prime minister challenging a decision to ban journalists from entering the Gaza Strip over the past two weeks.

The Israeli government has come under strong international criticism this week, including from Ban Ki-moon, the UN secretary general, over its tight blockade on the overcrowded strip of Palestinian territory.

A ceasefire between Israel and Hamas, the Islamist group which won Palestinian elections nearly three years ago and controls Gaza, effectively broke down two weeks ago after an Israeli raid killed six Hamas militants.

Since then there have been more Israeli raids, killing a total of around 17 Hamas gunmen, and Palestinian militants have fired dozens of rockets into southern Israel, injuring several people. Israel has kept its crossings into Gaza largely closed, allowing in only limited amounts of food and aid and keeping journalists out.

The Associated Press, Reuters, CNN, the BBC and other major news groups sent a letter yesterday to Ehud Olmert, the Israeli prime minister, calling for access to Gaza for all reporters. "We are gravely concerned about the prolonged and unprecedented denial of access to the Gaza Strip for the international media," the letter said.

"We would welcome an assurance that access to Gaza for international journalists will be restored immediately in the spirit of Israel's long-standing commitment to a free press."

It is the first time in several years that Israel has prevented foreign journalists from entering Gaza for such a long period, although Israeli journalists have been banned for at least two years. Israeli officials say the decision is because of rocket fire from Gaza into southern Israel, although similar bans have not been imposed in the past during periods of heavier fighting.

"There is no policy to prevent the media from entering Gaza, and the minute the security situation allows for the normal functioning of the crossings, journalists, like all of the others who have been inconvenienced, will be able to return to using the crossings," said Mark Regev, a spokesman for the Israeli prime minister.

However, Shlomo Dror, a spokesman for Israel's defence ministry, suggested Israel was not happy with press coverage from Gaza.

"Where Gaza is concerned, our image will always be bad," he said. "When journalists go in it works against us, and when they don't go in it works against us."

Journalists working in Israel and the Palestinian territories have to pass a security check to receive an Israeli government press card and must sign a censorship form agreeing to submit articles, photographs and recordings relating to "security and defence matters" - although in practice that rarely happens. As of last month journalists have also had to submit copies of their previous stories or reports.

Reports in Israel today said Olmert and his defence minister, Ehud Barak, held a secret meeting in Amman on Tuesday with Jordan's King Abdullah, who pressed Israel not to mount a large-scale invasion of Gaza. However, Olmert reportedly told the Jordanian king "there may not be any choice" but to invade.

As a result of the closure of crossings the UN Relief and Works Agency, which supports Palestinian refugees, had to briefly suspend its food distribution programme last week - the agency feeds 750,000 Gazans. Israel has severely limited fuel supplies into Gaza, which are used for the strip's sole power plant - though electricity also enters by lines from Israel and Egypt. The Associated Press reported from Gaza there were now blackouts of between 16 and 20 hours a day as well as widespread shortages of kerosene and cooking gas.

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