The reports are likely to fuel fears of a renewed arms race on the subcontinent.

In a recent classified briefings at the US Congress, lawmakers were presented with evidence that China has continued to ship guidance and other systems to Pakistan, also offering technical expertise, the reports said.

Chinese experts had also been sighted around Pakistan's newest missile factory, which appears to be based on a Chinese design, the New York Times quoted intelligence officials as saying.

The allegations will be discussed in detail by a high-level US team which is due in Beijing this week, the paper said.

US government officials on Sunday could confirm neither that the visit was scheduled nor the reports of secret briefings on the issue.

Fears that a new arms race could worsen the already brittle relations between arch rivals India and Pakistan were sparked when the two sides carried out tit-for-tat nuclear tests in 1998.

Both sides have said they want to avoid a missile buildup, but earlier this month India successfully test-fired its own short-range surface-to-surface Prithvi (Earth) missile, which in some models is nuclear capable.

Rumours that China has been helping Pakistan to build missiles have been circulating here over the last week, but officials habitually refuse to comment publicly on intelligence issues.

One administration official however told Sunday's Washington Post : "China's overall record in the non-proliferation area is very good," but added "the missile area remains a particular concern, particularly with Pakistan.

Pakistan's embassy in Washington issued a statement on Wednesday denying claims that China is aiding its missile program.

"These reports are completely baseless. It is also regrettable that these false reports have been used to mislead the US Senate and criticize Pakistan."

The statement added that cooperation between Pakistan and China was consistent with their respective international obligations.

Accusations on Beijing's record on weapons proliferation are likely to further complicate efforts to push a bill granting permanent normal trade relations (PNTR) to China through the Senate.

The bill is currently stalled in a legislative logjam.

The reports could also bolster support for a measure framed by Senator Fred Thompson of Tennessee, a Republican, which would force the president to restrict access to US financial markets to Chinese companies if Beijing is proved to have spread weapons technology.

Thompson has threatened to bring up the measure as an amendment to the PNTR bill if he is not allowed a separate vote on the issue.

PNTR for China has already passed in the House of Representatives,

The reported visit of the US delegation to China would include the first high-level negotiations on arms control since November 1998. The contacts have been suspended since NATO bombed the Chinese embassy in Belgrade last year during the Kosovo campaign.

The US insists the bombing was an accident, but the incident severely disrupted US-China relations.

Sattar dismissed recent US press reports that Beijing is helping Islamabad develop long-range missiles capable of carrying nuclear weapons, saying "at the present moment there is no such cooperation."

"This news report ... is not new in its substance," he told a press conference here.

"Pakistan's progress is now by the grace of God sufficiently advanced so that we can continue the process of research ourselves."

Newspaper reports on Sunday said US lawmakers had been shown evidence that China has continued to ship guidance and other systems to Pakistan as well as offering technical expertise.

Chinese experts had been sighted around Pakistan's newest missile factory, which appears to be based on a Chinese design, the New York Times quoted intelligence officials as saying.

The allegations will be discussed in detail by a high-level US team which is due in Beijing this week, the paper said.

Rumours that China has been helping Pakistan to build missiles have been circulating in Washington over the last week, but officials habitually refuse to comment publicly on intelligence issues.

"China's overall record in the non-proliferation area is very good," one administration official told the Washington Post.

But he added: "the missile area remains a particular concern, particularly with Pakistan."

Sattar said that in 1993, when he was briefly foreign minister in a previous government, the issue of China's assistance to Pakistan on missile development had been a bone of contention between Islamabad and Washington.

"China and Pakistan explained at that time that China had supplied a limited number of short-range tactical missiles to Pakistan which did not violate the MTCR (Missile Technology Control Regime) that China had accepted," he said.

"Since then there has been no allegation to the best of our knowledge against China having done anything inconsistent with its commitment to the MTCR.

"I can confirm that Pakistan has not received any transfers inconsistent with China's obligations under the MTCR."

Pakistan and India are the world's newest nuclear states after they conducted tit-for-tat tests in 1998, sparking international fears of a South Asian arms race between the bitter rivals.

Pakistan last month did not reply in kind to an Indian missile test and consistently says to is only interested in maintaining an effective deterrent against attack from its much larger neighbour.

China has helped develop a nuclear power plant in Pakistan and has been a strong ally over the years in a bid to counter the equally cosy relationship between India and Russia.

Military ruler General Pervez Musharraf said Saturday that Pakistan is planning to buy sophisticated F-7MG fighter jets from China but the move should not affect relations with the United States.