A Syrian boy mourns in the rubble of a building following a reported air strike by government forces on the rebel held area in the east of the northern Syrian city of Aleppo on April 13, 2015A Syrian boy mourns in the rubble of a building following a reported air strike by government forces on the rebel held area in the east of the northern Syrian city of Aleppo on April 13, 2015 (AFP Photo/Karam al-Masri)
Beirut (AFP) - A monitor and Syria's opposition have called for an investigation into a US-led coalition strike last week that allegedly killed 64 civilians, nearly half of them children, in northern Syria.
The US military on Sunday acknowledged coalition strikes in the Birmahle area but said it was unaware of any civilian deaths.
The Syrian Observatory for Human Rights, a Britain-based monitor that tracks deaths in the war, said the strikes in the village in Aleppo province overnight Friday needed to be investigated.
"We call for a serious investigation into what happened with the strikes on Birmahle, because this is a massacre," Observatory director Rami Abdel Rahman told AFP.
Syria's opposition National Coalition, which is backed by Washington, said it could not be certain who was behind the raids on Birmahle.
But it said available information "lends credence to reports that it was a US-led coalition air strike".
"It is absolutely vital, therefore, that such reports are taken seriously and a full investigation into the incident is carried out immediately," Coalition spokesman Salem Al-Meslet said in a statement.
The Observatory reported Saturday that the US-led coalition fighting the Islamic State group had killed dozens of civilians in strikes on Birmahle between April 30 and May 1.
On Monday, Abdel Rahman said the toll had risen to 64 civilians, including 31 children, with no IS fighters among the dead.
The Observatory relies on a broad network of sources, who Abdel Rahman said are able to identify air strikes by the coalition.
A US military spokesman said Sunday that 50 IS fighters had been killed but "we currently have no indication that any civilians were killed in these strikes."
He added that Kurdish forces had "reported that there were no civilians present in that location."
Abdel Rahman said Kurdish militiamen and Syrian rebel fighters based nearby had given the coalition inaccurate information regarding IS positions in Birmahle.
"They told the coalition that there was a convoy of 10 IS cars entering the village in the middle of the night, but village residents said only a few cars unaffiliated with IS had entered," he said.
IS had advanced in areas around Birmahle throughout the day before the strikes, but the group had no positions within the village itself, he said.
A spokesman for the Kurdish People's Protection Units (YPG) denied that Kurdish forces were in the area and said there was no coordination with the coalition on Birmahle.
"Of course there is coordination for other areas, but the YPG did not provide the coalition with information about this village," Redur Khalil told AFP by phone.
Prior to the strikes on Birmahle, coalition raids had killed 66 civilians since it began attacking IS positions in Syria in September 2014, the Observatory said.