Syria conflict: Deadly blast near Turkey border crossing
At least 43 people have been killed in a car bombing near the border between Syria and Turkey, activists say.
A car filled with explosives was reportedly blown up in the Karaj Sajou area, near the Bab al-Salam crossing in the northern province of Aleppo.
The UK-based Syrian Observatory for Human Rights reported that five women and three children were among the dead.
A video posted online appeared to show smoke rising from burning vehicles, charred corpses and scattered luggage.
"Oh God, may you punish them!" one man can be heard shouting.
The head of the Syrian Observatory, Rami Abdul Rahman, told the Associated Press that the explosion occurred at a garage used by passengers heading to or coming from the border crossing.
It was not immediately clear if it had been a suicide bombing, he added.
The governor of the Turkish province of Kilis told the state news agency Anadolu Agency that 48 injured Syrians had been transported across the border for treatment, and that 11 of them had later died.
Suleyman Tapsiz added that initial reports indicated the jihadist Islamic State in Iraq and the Levant (ISIS) was behind the bombing.
Bab al-Salam is under the control of the Tawhid Brigade. It is part of the Islamic Front, whose fighters have been engaged in deadly battles with ISIS since early January. The jihadists have been widely condemned for attacking fellow rebels and abusing civilians.
The area around Bab al-Salam has been bombed on several occasions. In February, an explosion killed six people and wounded 45 others.
It is the main route into Turkey for Syrians wanting to flee the three-year conflict in the country, which has left an estimated 150,000 people dead.
There are currently more than 742,000 refugees registered with the UN in Turkey. The Turkish government has set up 22 camps in 10 provinces to help accommodate about 220,000 of them.
Meanwhile in London, Turkey's foreign minister attended a meeting of 11 nations in the Friends of Syria Core Group, which agreed to step up support for the Syrian opposition.
US Secretary of State John Kerry said he was open to the idea of providing assistance through "any means", but stopped short of promising military aid to rebel fighters.
Mr Kerry also said he had seen raw, unverified data that suggested the Syrian government had used chlorine gas in attacks against its own people a number of times.
More than 100 civil society groups from around the world issued an appeal to the UN Security Council to approve a resolution, supported by a broad coalition of countries, referring the conflict in Syria to the prosecutor of the International Criminal Court (ICC).
"Neither Syrian authorities nor the leaders of non-state armed groups have taken any meaningful steps to ensure accountability for past and ongoing grave human rights crimes," the groups warn.
"The failure to hold those responsible for these violations to account has only fuelled further atrocities by all sides."
Syria is not a party to the Rome Statute, the treaty establishing the ICC.
Later, Medecins Sans Frontieres (MSF) confirmed that five staff abducted in north-western Syria in January had been safely released.
Three were freed on 4 April, while the other two were freed on Wednesday and were now on their way to be reunited with friends and relatives, the medical charity said in a statement.
It strongly condemned the "cynical act", which forced it to permanently close one hospital and two health centres in the Jabal Akrad region.