Syria field hospital hit by car bomb near Turkey
Several people are reported to have been killed by a car bomb near a field hospital in northern Syria, close to the border with Turkey.
Activists said the blast happened in the rebel-held town of Atmeh, which hosts a camp for thousands of people displaced by Syria's civil war.
It was not immediately clear who had carried out the attack.
On Saturday, the UN Security Council unanimously approved a resolution on access to humanitarian aid in Syria.
It was the first time the council has united on the issue.
Witness Abdallah Saleh said Sunday's blast damaged the hospital and caused 50 casualties, although it was not clear how many people had died.
Ambulances cross border
The Turkish Anadolu news agency said several people were killed and wounded and one unconfirmed report said nine people had died.
Other reports said Turkish ambulances had raced across the border to help the wounded.
According to UN figures, 6.5 million Syrians have been displaced by Syria's civil war and 2.5 million are registered as refugees.
Lebanon has taken the highest number of refugees, followed by Jordan and Turkey.
Saturday's UN resolution says both Syrian government and opposition forces must allow aid convoys to reach civilians across the country.
The agreed text does not threaten sanctions but warns of "further steps" if the sides do not comply.
Russia and China, which both vetoed previous similar resolutions, voted in favour.
Moscow, which has so far backed the government of President Bashar al-Assad, supported the document after insisting that an initial reference to sanctions be dropped.
In a separate development, a senior al-Qaeda operative has been killed in a suicide attack in the Syrian city of Aleppo.
Abu Khaled al-Suri died when two militants blew themselves up in a compound of his militant group, Ahrar Al-Sham.
His supporters have blamed another militant group, the Islamic State of Iraq and the Levant, known as ISIS, for the attack.
ISIS is engaged in a bloody power struggle with rival factions in the Syrian rebellion.
There was no immediate claim of responsibility for the killing but Al-Suri's death could further complicate efforts to resolve the infighting which has undermined rebel efforts to oust President Assad.
Ahrar al-Sham is a prominent, hard-line rebel group, part of a powerful alliance of seven groups known as the Islamic Front.