Israel has conducted an air strike in Syria, apparently targeting a building, according to CNN, although there has not yet been any official confirmation.
The network said US officials did not believe Israel had targeted a chemical weapons facility. CBS News cited US sources as saying Israel targeted a warehouse.
But Syrian UN Ambassador Bashar Ja'afari told Reuters, "I'm not aware of any attack right now."
A White House spokeswoman referred questions on the CNN report to the Israeli government.
The Pentagon declined comment.
In Jerusalem, a Israeli military spokeswoman declined to comment.
More top news
Jeremy Corbyn is facing increased pressure to resign as Labour leader.
Another unsettled day with cloud, rain and blustery winds.
Charaf Elmoudden, 26, has been found guilty at Harrow Crown Court of burgling pop star Rita Ora's home.