Residents begin to return after truce is extended in Syria's Aleppo

A general view shows a damaged street with sandbags used as barriers in Aleppo's Saif al-Dawla district on March 6, 2015.

Displaced families returned home and schools reopened in rebel-held districts of Syria's Aleppo on Saturday after a truce was extended for 72 hours in the battleground northern city.

Residents trickled back into eastern areas of Aleppo, encouraged by a halt in the deadly violence that hit last month, an AFP reporter said.

More than 300 civilians were killed in two weeks of fighting in the divided city before the truce took hold on Thursday, with regime air strikes on its opposition-held east and rebel shelling on its regime-controlled west.

"I decided to come home after relatives told me it was calm," father-of-six Abu Mohammed said.

"We left because it was carnage here. The air strikes were incredible," said the resident of the rebel-held Kalasseh neighbourhood.

The international community hopes that a drop in fighting can revive faltering peace talks to end a five-year war that has killed more than 270,000 people and displaced millions.

Schools in Aleppo's east reopened on Saturday after staying closed for more than two weeks, the AFP reporter said.

"Almost all students have come back, apart from those who fled their neighbourhoods," a primary school teacher in the Shaar district said.

Russia's defence ministry said the truce had been extended "in order to prevent the situation from worsening" just minutes before the initial 48-hour truce for the city was due to expire.

"The regime of silence in the province of Latakia and in the city of Aleppo has been extended from 00:01 (local time) on May 7 (2101 GMT Friday) for 72 hours," the ministry said in a statement.

Violence in the city last month severely threatened a nationwide ceasefire between President Bashar al-Assad's regime and non-jihadist rebels.

The United States -- which has been working with Moscow to pressure the regime to stop the violence and revive the February 27 cessation of hostilities -- also confirmed the extension.

"While we welcome this recent extension, our goal is to get to a point where we no longer have to count the hours and that the cessation of hostilities is fully respected across Syria," US State Department spokesman John Kirby said.

But fighting rages on in other parts of Syria including in the rebel bastion of Eastern Ghouta outside Damascus and on the outskirts of Aleppo city, the Syrian Observatory for Human Rights said.

In the north of Aleppo province, six people including women and children were killed in night air raids -- apparently by the US-led coalition -- on two Islamic State (IS) group strongholds, the British-based monitor said.

Twelve IS fighters were also reported to have died in a battle against rebels.

In the central city of Hama, a raid by Syrian security forces on a prison failed to end a mutiny there involving around 800 mostly political detainees.

Ten guards were taken hostage after the violence broke out on Monday following an attempt to transfer detainees to another prison near Damascus where numerous executions of inmates have been reported.

IS fighters meanwhile clashed with regime forces near the divided eastern city of Deir Ezzor on Friday, the Observatory said.

The violence killed five jihadists and around 10 pro-regime fighters, whose bodies IS displayed on the walls of a public garden in the city, the monitor said.

An international outcry has grown over air strikes Thursday on a camp for the displaced near the Turkish border that left at least 28 dead including women and children.

Anti-regime activists have blamed the regime, but the Syrian military has denied the accusation.

Russia's military insisted no aircraft flew over the camp on Thursday, suggesting Syria's Al-Qaeda affiliate Al-Nusra Front could have shelled it.

The United States has said that the circumstances are unclear.

"We're still gathering information right now and are not in a position to definitively say exactly what happened there," Kirby said.

Regime aircraft have previously targeted rebels other than Al-Nusra and IS, which are not covered by the February 27 ceasefire.

Russia also launched air raids in support of Damascus in September, and a US-led coalition has conducted air strikes against IS in Syria since 2014.

UN Secretary General Ban Ki-moon said he was "outraged" by the attack on the camp and those responsible must face justice.

Ban demanded once again that the UN Security Council refer Syria to the International Criminal Court so that the tribunal based in The Hague can open investigations into possible war crimes.