Syria is producing chemical weapons, a U.S. official said yesterday, signaling a potentially significant complication in U.S.-led efforts to control proliferation of the weapons.

The disclosure was made at a briefing at the State Department on the status of U.S. arms control negotiations. The official, who refused to be identified by name, was asked whether Syria was producing chemical weapons or getting them from another country. "Yes," the official responded, "they are producing chemical weapons."

When asked where Syria obtained components for the wea- pons, he replied: "From a variety of places. I can't get into that because it gets into sources and methods."

Asked whether Syria is transferring any of the weapons to Iran, the source said, "I think I had better not answer that question."

Syria has been an ally of Iran in its Persian Gulf War with Iraq. The United States has accused Iraq of using chemical weapons in the war, which has lasted six years.

Earlier this year, Kenneth L. Adelman, director of the Arms Control and Disarmament Agency, said that more than 15 nations are thought to possess chemical weapons, compared with five nations in the early 1960s. Last month, House Foreign Affairs Committee Chairman Dante B. Fascell (D-Fla.) urged the administration to accelerate its efforts at the Geneva arms negotiations to ban chemical weapons.