A suicide bomber from Syria's al-Qaeda offshoot - the Nusra Front - has blown himself up at an army outpost in a contested neighbourhood of northern city of Aleppo, killing at least 25 soldiers and allied militia, a monitoring group says.
Monday's blast in Aleppo, which is divided among rebel groups and government forces, also injured scores, the UK-based Syrian Observatory for Human Rights, which tracks the violence across the country, said on Monday.
The Observatory said that the explosion from the blast was heard across the city where several armed groups had recently launched an offensive to control the remaining western parts of the city which are in government hands.
Rebel websites said there was heavy bombardment of rebel-held portions of Jamiyat al-Zahra district, where rebels had gained ground and brought them closer to the heart of government-controlled parts of the city, which before the 2011 civil war was the country's main industrial and commercial hub.
Intensifying anti-ISIL campaign
The attack comes as President Barack Obama pledged to increase US support for the moderate opposition in Syria's civil war, and said that the US-led coalition battling fighters from the Islamic State of Iraq and the Levant (ISIL) was "intensifying" its campaign against the armed group's base in Syria.
"And I have made it clear to my team that we will do more to train and equip the moderate opposition in Syria," Obama, speaking at the Pentagon, said.
And I have made it clear to my team that we will do more to train and equip the moderate opposition in Syria.
He said that the US would continue to crack down on ISIL's illicit finance operations around the world.
There are no current plans to send additional US troops overseas, he said, repeating that the fight against the armed group would not be quick.
The US president reiterated that with a strong partner on the ground in Iraq, the US and its partners would be successful in defeating the armed group.
He said the training of such forces had been ramped up after a period that was too slow and that the fall of Ramadi, the capital of the predominately Sunni western Anbar province, had galvanised the Iraqi government.
"More Sunni volunteers are coming forward," he said. "Some are already being trained and they can be a new force against ISIL. We continue to accelerate the delivery of critical equipment, including anti-tank weapons, to Iraqi security forces.