United Nations experts are investigating the alleged use of chemical weapons in Syria as the United States and its allies prepare for the possibility of a punitive strike against President Bashar Assad’s regime, blamed by the Syrian opposition for the attack. The international aid group Doctors Without Borders says at least 355 people were killed in the Aug. 21 attack.

Here’s a look at key Syria developments around the world Friday amid heightened tensions over potential military action:


Treasury chief George Osborne warned that Britain should not turn its back on the world after the stunning parliamentary defeat of a government motion for military intervention in Syria. He told the BBC there will be “national soul-searching” about Britain’s global role after the “no” vote.


U.N. experts delayed the start of their final day of investigations into last week’s suspected chemical weapons attack in a suburb near the Syrian capital of Damascus. A convoy of U.N. vehicles left the inspectors’ hotel in central Damascus early Friday, but returned minutes later. It was not clear why the team turned back, and the U.N. could not be reached for comment.


Ahmad al-Jarba, the head of the Western-backed Syrian opposition, said the British Parliament’s failure to endorse military action in Syria isn’t enough to hold back strikes by other allies. He told France-Inter radio that strikes contemplated by the United States, France, and, originally, Britain are a moral responsibility that can level the playing field militarily.


President Barack Obama prepared for the possibility of launching unilateral American military action against Syria within days as Britain opted out. Top U.S. officials spoke with certain lawmakers for more than 90 minutes in a teleconference Thursday evening to explain why they believe Bashar Assad’s government was the culprit in the suspected chemical attack last week.


Supporters of Syrian President Bashar Assad planned a rally after Friday prayers at Tehran University. The demonstration was not directly backed by the government, which is a close Syria ally, but it would not be allowed to take place without permission from authorities.

For an AP Interactive Graphic about Syria, go to postandcourier.com/syria