INCIRLIK, TURKEY - Military planes flew over Turkey's Incirlik air base on August 31 as the United States made clear on August 30 that it would punish Syrian President Bashar al-Assad for the "brutal and flagrant" chemical weapons attack that it says killed more than 1,400 people in Damascus last week.
Incirlik is a NATO air base outside the city of Adana where U.S. troops are also stationed.
It is located in southern city of Adana, some 100 km (62 miles) from the Syrian border.
Earlier this year, some of the Dutch Patriot missile systems were set up in Incirlik air base in a move aimed at bolstering Turkey's defense against a threat of air attacks from Syria.
President Barack Obama told reporters on Friday at the White House the United States was still in the planning process for a "limited, narrow" military response that would not involve "boots on the ground" or be open-ended.
He set no timetable for action.
In a sign the United States may be preparing to act, a senior State Department official said Secretary of State John Kerry spoke on Friday to the foreign ministers of Britain, Egypt, Germany, the Netherlands, New Zealand, Saudi Arabia and the United Arab Emirates as well as to the secretary general of the Arab League.
The White House will brief Republican senators on Syria in a conference call on Saturday at the request of Senate Minority Leader Mitch McConnell, a spokesman for the senator said.
Most officials who talked to Reuters said the possibility of allied and civilian casualties was a top consideration.
Manned aircraft could still be ultimately used - Israeli jets have already raided Syrian targets on several occasions, proving it is possible.
U.S. F-16 jets have remained in Jordan after an exercise earlier this year.
The U.S. air force could also reinforce its Turkish air base at Incirlik while B2 long-range bombers could fly from the continental United States, unseen by Syrian radar.
Turkish Prime Minister Tayyip Erdogan said August 30 that any international military intervention against Syria should be aimed at bringing an end to Assad's rule.
Earlier, Turkish Foreign Minister Ahmet Davutoglu said intelligence gathered by Ankara left no doubt that Assad's forces were responsible for the poison gas attack near Damascus last week.
Turkey has said previously it would be ready to take part in any international action against Assad, even outside the auspices of the United Nations, and has put its armed forces on alert to guard against threats from Syria.
Incirlik air base had been used during US no fly zone over Northern Iraq for fighter jets patrolling during the mission.