The United States has complained to China about a report that China may be supplying raw materials for chemical weapons to Libya, informed U.S. officials said yesterday.

Assistant Secretary of State Richard H. Solomon told a Senate Foreign Relations subcommittee that the United States has "some indications that something may be going on in that area, and we have expressed concerns" to China "at a very high level." Solomon was not more specific in responding to a question from Sen. Joseph R. Biden Jr. (D-Del.) about China's involvement in "poison gas."

But other officials said later that a U.S. intelligence report suggested recently that China may be selling chemicals needed to make weapons to Libya. The officials said the report was not substantiated but was serious enough to warrant a complaint.

Within the last few days, Under Secretary of State Reginald Bartholomew met with Chinese Ambassador Zhu Qichen to convey U.S. concern, officials said. The ambassador responded by reiterating Chinese statements that China is not a chemical weapons provider, officials said.

About three months ago, officials said, there was another intelligence report that indicated a Chinese company presence at Rabta, the chemical and industrial complex that the United States has said may include a chemical weapons factory. The company is involved in artillery, officials said, leading to speculation that it was assisting Libya leader Moammar Gadhafi in building chemical weapons.

Rabta was the scene of what U.S. and Libyan officials at first said was a fire on March 14. The Bush administration later withdrew that assessment and said the fire might have been a hoax perpetrated by Gadhafi. The Libyan leader has said the factory produces only pharmaceuticals. President Bush has charged that it is producing chemical weapons.

At a hearing on Sino-American relations one year after China's crackdown on pro-democracy demonstrators, Biden claimed that Beijing has been unresponsive to previous U.S. complaints about involvement in missile exports to the Middle East and nuclear and chemical weapons. Biden said China is "engaged in several very dangerous military relationships with countries in the Middle East and Southwest Asia." He added, "I've seen nothing that has indicated that the Chinese have ever responded to the concerns" voiced by the United States.

Solomon said that with the exception of one missile deal with Saudi Arabia, "we are not aware of other missile exports to the Middle East." He said the United States would insist that China stick by a pledge made last year not to export such weapons to the region.

Also yesterday, the panel heard from Chai Ling, 24, one of the leaders of the pro-democracy movement who spent 10 months in hiding and later fled China to exile in Paris. She said there remains "widespread dissatisfaction" among "all strata" of Chinese society.

Asked by Sen. Alan Cranston (D-Calif.) whether Congress should renew most favored nation trading status for China, as Bush has recommended, Chai Ling said it should be linked to some conditions for human rights improvement. "The best way is to connect these," she said.

Staff writer R. Jeffrey Smith contributed to this report.