The violence in Syria threatens an uneasy truce in neighbouring Lebanon where guns have reappeared on the streets after years of peace.
There has been violence in the Lebanese capital Beirut today following the funeral of a security chief whose death many blame on Syria.
For the people of Beirut, Friday's car explosion is a bloody and terrifying throwback to the bad old days of civil war.
An unarmed Lebanese protester has been shot dead in front of the Iranian Embassy in Beirut, Lebanese security officials said.
It was not clear who killed the man, who was a member of a small crowd demonstrating against Iran and Hezbollah's backing for Syrian President Bashar al-Assad.
Pro-Assad Lebanese gunmen were in the vicinity at the time of the killing, the sources said.
The White House has condemned "in the strongest possible terms" the Syrian Army's victory in the town of Qusair and has called on Hezbollah and Iran to immediately withdraw fighters from the country.
– White House Press Secretary
The United States condemns in the strongest possible terms the Assad regime’s assault on Qusair, which has killed untold numbers of civilians and is causing tremendous humanitarian suffering. The Syrian Arab Republic Government and other parties to this conflict have an obligation under international human rights and humanitarian law to immediately allow neutral, impartial humanitarian organisations, including UN agencies, safe access to evacuate the wounded and provide life-saving medical supplies and treatment.
Syrian rebels fighting to overthrow the regime of President Bashar al-Assad suffered a significant defeat when they were pushed back from the strategically important town of Qusair, which they had held for more than a year.
ITV News reporter Neil Connery on why the loss is so important:
Syrian and Lebanese TV stations are carrying images from the town of Qusair after pro-government forces drove out rebels.
Many of the buildings, including a mosque, have been seriously damaged by shelling and the streets are full of rubble.
Syrian rebels confirmed to Reuters that they had pulled out of the strategically-important town of Qusair "in face of this huge arsenal and lack supplies".
They also blamed the "blatant intervention" of the Lebanese militant group Hezbollah for their defeat.
The statement added: "Dozens of fighters stayed behind and ensured the withdrawal of their comrades along with the civilians."
Soldiers loyal to Syrian President Bashar al-Assad have been celebrating victory in the streets of the strategic town of Qusair in the west of the country.
Lebanon's Hezbollah-backed TV station Al Manar has been showing footage of soldiers sticking Syrian flags with photographs of Assad on piles of rubble in the badly-bombed town.
The town, which lies close to the border with Lebanon and a critical supply route, has seen intense fighting for more than two weeks.
Syrian state TV carried a statement from the military saying: "Our heroic armed forces have returned security and stability to all of the town of Qusair."
Two rockets hit a Hezbollah-controlled district in the southern part of Lebanon's capital on Sunday, residents said, wounding several people.
The attack may have been a response to a speech by the militant group's leader Hassan Nasrallah a day earlier, in which he committed to fighting in Syria's conflict on behalf of his ally President Bashar al-Assad.
Two rockets have hit a Hezbollah-controlled district in southern Beirut, in apparent response to the group's commitment to fight in Syria, say local residents.
Lebanon's prime minister Najib Mikati has resigned.
The US State Department has confirmed it believes that Syrian government aircraft fired rockets into northern Lebanon.
State Department spokeswoman Victoria Nuland described the incident as "a significant escalation."