United Nations experts are investigating the alleged use of chemical weapons in Syria as the United States and 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 August 21 attack.
Here is a look at key Syria developments around the world on Thursday and Friday amid heightened tensions over potential military action:
SYRIA:
Assad said his country "will defend itself against any aggression", signalling defiance to mounting Western warnings of a possible punitive strike. UN chemical weapons inspectors toured stricken rebel-held areas near the Syrian capital of Damascus for a third day.
BRITAIN:
The British Parliament voted down endorsing military action against Syria, despite a strong push by Prime Minister David Cameron to support potential US strikes against Assad. Defence Secretary Philip Hammond confirmed that the country's forces would not be involved in any strike.
FRANCE:
The French military is ready to commit forces to an operation in Syria if president Francois Hollande approves it, defence minister Jean-Yves Le Drian said. Mr Hollande, who met with the head of the Syrian opposition, stopped short of announcing a military intervention.
UNITED NATIONS:
A meeting of the UN Security Council's permanent members ended quickly with no sign of progress on an agreement over Syria's crisis. UN experts in Syria are expected to leave the country on Saturday.
ISRAEL:
Thousands of Israelis crowded gas mask distribution facilities to get free masks, fearing Israel could be targeted in retaliation by Syria if it is attacked. A mob forcibly took gas masks from a distribution centre in Jerusalem on Wednesday. Officers were deployed to maintain order on Thursday in Haifa, where more than 5,000 people waited for protective kits.
TURKEY:
Officials placed Turkey on alert against possible chemical attacks from Syria and stocked food and gas masks along their shared border. Bunkers were designated in seven border areas to protect people in the area from harm.
IRAN:
President Hassan Rouhani said his country will press forward with efforts to ward off military action by the US and its allies against the Tehran-backed Syrian regime.
UNITED STATES:
White House officials said President Barack Obama was preparing for the possibility of launching unilateral American military action against Syria within days, even as the British Parliament rejected sending its forces to support a military strike. Mr Obama also spoke by phone with Republican House Speaker John Boehner, who has asked the president to make a sharper case on the legal justification for any military strike in Syria and its objective. The administration shared intelligence with politicians aimed at convincing them Syria's government used chemical weapons in last week's attack.
RUSSIA:
Russia's foreign ministry asked the UN to continue its inspection of places where chemical weapons might have been used in Syria. A foreign minister spokesman said the team should inspect three other locations, including a suburb of Aleppo, where the government in Damascus alleges the rebels have used poisoned gas.
GERMANY:
A poll by ZDF television found that a majority of Germans oppose Western military intervention in Syria and do not want their country to provide backing for any US-led strike.
LEBANON:
Lebanese foreign minister Adnan Mansour said any international military action against Syria would pose a "serious threat" to the security and stability of the region, particularly Lebanon.
EGYPT:
Egyptian foreign minister Nabil Fahmy said his country strongly opposes military action against Syria and would not support possible punitive strikes by the US and its allies against the Syrian regime.
ROMANIA:
Romania's foreign ministry told its citizens in Syria to leave the country "as soon as possible". They were told to get out via Lebanon, Jordan and Turkey.