Fierce clashes raged overnight on the edges of Syria's second city Aleppo after a major opposition offensive, an AFP correspondent said Wednesday.

A coalition of opposition groups fighting under the name "Fatah Halab" launched the assault on Bashar al-Assad's forces with a tunnel bomb on Tuesday.

Opposition fighters initially advanced from the western suburbs of the city into regime-held districts but were pushed back by Wednesday morning, the Syrian Observatory for Human Rights said.

Observatory head Rami Abdel Rahman said the fighting was "the most violent in Aleppo in over a year."

The Britain-based monitor did not have an immediate count for combatants killed.

The intense clashes lasted through the night, with heavy artillery shelling and air strikes heard throughout the battered metropolis, an AFP correspondent in the city said.

Air strikes on opposition-controlled eastern neighborhoods subsided as regime warplanes focused on the fight in the west, he said.

By the morning, the clashes had quieted but weary residents were not expecting calm for long.

"I don't think the air strikes will stop, because the decision to stop firing isn't in Assad's hands -- it's in the hands of his Russian ally," said Mahmoud Sendeh, a 26-year-old activist in Aleppo's eastern districts.

"Up until now, it looks like Russia doesn't want calm to return to Aleppo," Sendeh told AFP.

Nearly two weeks of renewed fighting in Aleppo have left more than 270 civilians dead.

On Wednesday morning, three civilians were killed and one person wounded when opposition rocket fire crashed into a regime-held neighborhood, state news agency SANA said.

Washington and Moscow are working together to include Aleppo in a so-called "regime of silence" -- a freeze in fighting -- aimed at bolstering a broader truce in place since February 27.
Since 2012, Aleppo city has been divided by a front line separating regime forces in the west from opposition groups in the east.

But on the outskirts of the city, the inverse is true: opposition groups have nearly encircled the western half of Aleppo city, as regime forces have surrounded the eastern sides.

Opposition groups have tried to push in from the western suburbs into regime-held territory, including in a major assault a year ago that also began with a huge tunnel explosion.

PHOTO CAPTION

People walk on the rubble of damaged buildings after an airstrike in the opposition held area of Aleppo's Baedeen district, Syria, May 3, 2016. [Reuters]

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