DAMASCUS: Fighting raged in Syria's second city Aleppo on Monday, with the army claiming to have secured much of a strategic district, as the United Nations denounced gross human rights violations by both sides.

Meanwhile, peace envoy Lakhdar Brahimi, who just spent four days in Syria, was to meet with the Syria “contact group” in Cairo as it seeks ways to end the bloodbath.

The district of “Midan is under the control of the army,” a military official told AFP, in a report backed up by an AFP correspondent on the ground.

“We came back to our homes when we heard the army controlled Midan, but there was no electricity,” a man said. “We waited for two hours and it didn't return. We will go back when it is fixed.”

But not all areas were safe and an army checkpoint had been set up near the Midan police station, also retaken by the army, to prevent residents from returning to their homes in the so-called “fourth zone” of the district.

One man was turned away at an army checkpoint after being told there were still snipers in the area and it was not safe to enter.

The Syrian Observatory for Human Rights said four rebels were killed in fighting across the northern city, which has been the scene of battles since July 20.

A clash broke out near a building of the feared air force intelligence and rebels also attacked a military post in New Aleppo, as fighting took place in the northeastern district of Hanano, the western area of Zahraa and in Sukari to the south.

Two people were killed in shelling of the city's Sakhur neighbourhood, while a boy and girl died in bombing of the Aleppo provincial town of Kfar Hamra, the Observatory said.

The Britain-based monitoring group also reported that the army shelled the strongly pro-rebel district of Al-Hajar Al-Aswad in Damascus in preparation for storming it.

“According to initial reports, one person has been killed there, and several have been injured,” it said.

Shelling was also reported in several districts of the central city of Homs, which the army had claimed to have under its control.

In the northwestern province of Idlib, pro-regime gunmen killed three members of the same family in the town of Tamanaa, said the watchdog.

At least 54 people died nationwide on Monday, most of them civilians, the Observatory said, after 148 were killed the previous day.

The death toll from the 18-month conflict has risen to more than 27,000 people, says the Observatory, while the United Nations puts the figure at 20,000.

'Gross rights violations'

In Geneva, the head of a UN commission investigating rights abuses in Syria said they had soared dramatically in recent weeks and that the UN Security Council should take “appropriate action” against war criminals.

“Gross violations of human rights have grown in number, in pace and in scale,” Paulo Sergio Pinheiro said, adding President Bashar al-Assad's regime and rebels, to a lesser extent, had committed war crimes.

“In a dramatic escalation, indiscriminate attacks on civilians in the form of air strikes and artillery shelling levelled against residential neighbourhoods are occurring daily,” he said.

The indiscriminate use of weapons, he added, combined with a failure to protect civilians, reflected “a disturbing disregard for established rules of armed conflict.”

For its part, Human Rights Watch called on the Security Council to refer the situation in Syria to the International Criminal Court.

“This is one measure that all Security Council members, including Russia, should find it easy to agree on if they are truly concerned about the violations committed in Syria,” the New York-based group's Nadim Houry said in a statement.

“Extrajudicial or summary executions of detainees in the context of an armed conflict are war crimes, and may constitute crimes against humanity if they are widespread and systematic,” the statement said.

In Cairo, meanwhile, the foreign ministers of Egypt, Turkey and Iran were to meet to discuss developments in Syria on the political and humanitarian fronts, the Egyptian foreign ministry said.

Saudi Arabia is also a member of the group, but it was not immediately clear who would represent the kingdom at the talks.

Iranian Foreign Minister Ali Akbar Salehi is to meet Egyptian President Mohamed Morsi separately, Iran's official news agency IRNA reported.

Salehi told the ISNA news agency before leaving Tehran on Monday that Iran would be setting out its “clear” position on its ally Syria.

“We are very hopeful given that four important countries of the region are gathered to discuss one of the sensitive issues of the region,” he was quoted as saying.

Brahimi, who just spent four days in Syria, was to meet with the group, an Arab diplomat said. Brahimi said Saturday the “crisis is dangerous and getting worse, and it is a threat to the Syrian people, the region and the world.”