Undercover agents who infiltrated a Syrian-based terrorist group were exposed and killed, possibly because of information given to Syria by the United States, a newspaper reports.

The two or three undercover agents, believed to be working for Israel, were killed last fall after their covers were blown, The New York Times reported in Thursday's editions.Although a link has not been proved, U.S. authorities believe terrorists obtained information given to Syria by U.S. diplomats, as evidence to support charges of terrorist activity and used it to expose the agents, the Times reported, quoting Bush administration officials.

"It is a causal relationship," an unidentified official told the newspaper. "There is no doubt in my mind."

The agents killed were two or three Palestinians who had penetrated the terrorist group on behalf of Mossad, the Israeli intelligence agency, or a Western intelligence service, according to unidentified sources. The terrorist group was not identified.

"It's safe to say it hurt us," another unidentified official said.

The disclosures reportedly came in mid-September, after Syria had aligned with the United States in the coalition against Iraq.

The Times said several officials said the disclosures appear to have sprung from a protest about Syrian terrorist activities that U.S. Secretary of State James A. Baker III delivered to Syrian President Hafez Assad in Damascus.

It said Bush confronted him with evidence, based on intelligence, of terrorist activities in Syria.

Intelligence officials argued that telling Syria too much could endanger agents, operations and information gathering methods, the newspaper said.

The administration countered that the evidence given to Assad should be impressive.

Baker's spokeswoman, Margaret D. Tutwiler, refused to confirm that any deaths occurred, and said any suggestion that Baker supplied information "that led to the death of any individual is categorically untrue."