Senior State Department official Vann Van Diepen will head a US delegation at expert-level talks scheduled when Secretary of State Colin Powell met senior leaders in the Chinese capital last month.

At issue is compliance to a November 2000 deal under which Beijing undertook not to export nuclear-capable missiles and components in return for Washington waiving sanctions on Chinese firms it suspected of complicity in the trade.

The talks, which begin Thursday and could stretch into Friday, will include issues focusing on "implementation of the November 2000 arrangement," said State Department spokesman Philip Reeker Tuesday.

Domestic political pressure on Bush over the issue has been fanned by regular intelligence leaks in the US media.

The Washington Times quoted US intelligence officials this month as saying that a Chinese state firm had shipped 12 batches of missile components to Pakistan, in an apparent contravention of the deal.

China and the company concerned, the China National Machinery and Equipment Import and Export Corporation, denied the reports.

Van Diepen, acting deputy assistant secretary of state for non proliferation, headed to Beijing with the administration feeling heat on the issue from Congress.

Administration officials will not say if the issue of sanctioning specific Chinese firms is under consideration.

But an official told AFP last week that an "important" part of the Beijing talks will center on a proposed Chinese export control regime.

As they weigh their options, US officials must consider whether sanctions mandated under the Arms Export Control Act will be effective, or whether they will provoke China to step up its alleged proliferation.

Some experts believe that sanctions would cause more disturbance than they are worth.

That is because the Act simply prevents Chinese firms from procuring defense contracts and licenses from the United States and exporting military equipment into the country -- something they are unlikely to be doing anyway.

China argues that the United States has also failed to live up to its agreements under the November accord -- and has linked its alleged proliferation activities to alleged US arms sales to Taiwan -- a link Washington rejects.