U.S. Secretary of State John Kerry said on Tuesday that NATO needed to consider its role in the Syrian crisis, including how it would respond to a potential chemical weapons threat.
"We need to continue to consider NATO's role as it relates to the Syrian crisis," Kerry said in a statement prepared for a meeting of NATO foreign ministers in Brussels, adding that the planning that the alliance had already done was appropriate.
"We should also carefully and collectively consider how NATO is prepared to respond to protect its members from a Syrian threat, including any potential chemical weapons threat," he said.
NATO, a U.S.-led military alliance of 28 countries, has said repeatedly it has no intention of intervening militarily in the Syrian civil war. It has though sent Patriot missiles batteries to neighbouring Turkey to help defend the NATO member against possible missile attack from Syria.
Earlier on Tuesday, the Israeli military's top intelligence analyst said Syrian government forces had used chemical weapons - probably nerve gas - in their fight against rebels trying to force out President Bashar al-Assad.
Brigadier-General Itai Brun made the comments at a Tel Aviv security conference a day after U.S. Defense Secretary Chuck Hagel said on a visit to Israel that U.S. intelligence agencies were still assessing whether such weapons had been employed.
U.S. President Barack Obama has called the use of chemical weapons a "red line" for the United States that would trigger unspecified U.S. action.