The U.S. ambassador to Syria told Congress on Wednesday that there is so far no evidence to back reports that chemical weapons were used in Syria on Tuesday.

“So far, we have no evidence which substantiates the reports that chemical weapons were used yesterday. But I want to underline that we are looking very carefully at these reports,” Robert Ford, who was recalled from Damascus in February 2012, said during a U.S. House of Representatives hearing.

Separately, U.S. and European officials told Reuters there was no confirmation that either the forces of Syrian President Bashar al-Assad or his rebel opponents had used chemical weapons, as each side had asserted.

“We can’t corroborate the CW claims at this point,” one U.S. official said, speaking on condition of anonymity. Another official said the U.S. government was continuing to investigate.

Assad’s government and rebels accused each other of launching a deadly chemical attack near the northern city of Aleppo on Tuesday in what would, if confirmed, be the first use of such weapons in the two-year conflict.

The White House and State Department expressed deep skepticism over the Syrian government’s claims regarding the rebels.

“We view this issue with extreme seriousness,” Ford told the congressional hearing. “Right now we are trying to verify the reports we have seen recently about the use.”

“There are reports about them being used both in the north and in the Damascus suburbs, the eastern suburbs of Damascus,” he said.

U.S. President Barack Obama has warned there would be consequences if Syria uses chemical weapons, without spelling out what those would be.

Ford said Washington has regular discussions with countries that have interests in Syria, urging them to “pass the warning” to Assad and his government.

(Reuters)