The developments came within hours of Barack Obama's re-election, with U.S. allies anticipating a new, bolder approach from the American president to end the deadlocked civil war that has killed more than 36,000 people since an uprising against Assad began in March 2011.
British Prime Minister David Cameron, visiting a camp Wednesday for Syrian refugees in Jordan, said the U.S., Britain and other allies should do more to "shape the opposition" into a coherent force and open channels of communication directly with rebel military commanders.
Previously, Britain and the U.S. have acknowledged contacts only with exile groups and political opposition figures — some connected to rebel forces — inside Syria.
"There is an opportunity for Britain, for America, for Saudi Arabia, Jordan and like-minded allies to come together and try to help shape the opposition, outside Syria and inside Syria," Cameron said. "And try to help them achieve their goal, which is our goal of a Syria without Assad."
The Turkish official who reported Patriot missile discussions between his nation and its allies, including the United States, said planning for the safe zone inside Syria had been put on hold pending the U.S. election.
The foreign ministry official spoke on condition of anonymity because of ministry prohibitions on contact with the media.
He also said any missile deployment might happen under a "NATO umbrella," though NATO has insisted it will not intervene without a clear United Nations mandate.
"With the re-election of Obama, what you have is a strong confidence on the British side that the U.S. administration will be engaged more on Syria from the get-go," said Shashank Joshi, an analyst at London's Royal United Services Institute, a military and security think tank.
On the ground in Syria, rebels were making a new push into the capital Wednesday, clashing heavily with troops in the suburbs of Damascus, including Ghouta and Harasta. The regime's capital stronghold has seen a surge in violence this week with some of the fiercest clashes in months.
The Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees said the Syrian military was shelling another suburb, Beit Saham, with tanks and mortars, killing at least 18 people in that neighborhood alone.
In London, British Foreign Secretary William Hague said talks with rebel military leaders would not involve advice on military tactics or support for their operations. Hague also insisted that Britain would not consider offering weapons to Assad's opponents.
Face-to-face meetings with military figures will take place outside Syria, Hague said. Diplomats from the U.S., Britain, France and Turkey are already scheduled to meet with Syrian opposition groups on Thursday in Doha, Qatar, though there has been no announcement that those talks will include discussion with rebel fighters.
He said U.K. diplomats will tell rebel commanders to respect the human rights of captured Assad loyalists, amid concern over abuses carried out by both sides.
"In all contacts, my officials will stress the importance of respecting human rights and international human rights norms, rejecting extremism and terrorism, and working towards peaceful political transition," Hague told lawmakers.
At the Zaatari camp, which houses about 40,000 of the estimated 236,000 people who have fled into Jordan from Syria, Cameron said he would press Obama at the first opportunity to drive forward efforts to end the 19-month-old conflict.
Cameron plans to convene a meeting of Britain's National Security Council in London devoted entirely to Syria and discuss how the U.K. can encourage Obama to pursue a more direct strategy.
"Right here in Jordan I am hearing appalling stories about what has happened inside Syria, so one of the first things I want to talk to Barack about is how we must do more to try and solve this crisis," he said.
Talks with those who had fled the violence had redoubled his "determination that now, with a newly-elected American president, we have got to do more to help this part of the world, to help Syria achieve transition," Cameron added.
He flew to the camp by helicopter with Jordanian Foreign Minister Nasser Judeh and announced that Britain would offer an extra 14 million pounds ($22 million) in humanitarian aid, bringing its total funding to 53.5 million pounds ($85.5 million) — making it the second largest donor after the United States.
Cameron later held talks with Jordan's King Abdullah II in the capital, Amman.
Stringer reported from London. Associated Press writer Suzan Fraser in Ankara, Turkey, contributed to this report