Syrian rebels have captured an ammunition depot north of Damascus from government forces, activists said, seizing a hoard of anti-tank missiles and rockets which could strengthen their firepower after a string of defeats.

Video footage of the raid published on Saturday showed delighted rebel fighters carrying out boxes of weapons from the arms cache in Denha, near the town of Yabroud, following an overnight attack.

Still largely outgunned by Assad's forces, who have gained ground around the capital Damascus and Syria's third largest city Homs, the rebels have sought arms to tip the balance of power in the two-year conflict that has killed at least 100,000.

Saturday's raid yielded French-made Milan anti-tank missiles, Russian Konkurs missiles and Grad rockets, according to video footage which showed the rebels carrying off their haul through the dark corridors of the captured complex.

"Our return to Qusayr just got closer," shouted one fighter, referring to the former rebel stronghold and border town which was captured two months ago by Assad forces backed by the Lebanon's Hezbollah.

UN warning

Following their victory in Qusayr, south west of Homs, Assad's forces took control of several nearby towns and villages and on Monday they seized the Homs district of Khaldiya after weeks of urban warfare, tightening their siege on the few remaining rebel bastions in the strategic city.

"God willing, we will liberate Homs completely," the fighter in Saturday's video said.

We call on all parties to facilitate immediate safe access to these families so we can provide life-saving assistance Anthony Lake, UNICEF director

Homs lies on the main north-south highway which links most of Syria's main cities, and also forms a link between Assad's capital in Damascus and the heartland of his minority Alawite community in the mountains overlooking the Mediterranean.

In the same border region near Yabroud where the missile stocks were seized, Syrian jets killed at least nine peoplein an air strike, Lebanese security sources said. Some of the wounded had been brought into Lebanon for treatment.

Also on Saturday, UK-based the Syrian Observatory for Human Rights said government forces bombarded al-Qusour, one of the remaining rebel-held neighbourhoods.

In the northwestern Homs district of al-Waer, the United Nations children's agency UNICEF warned that 400,000 civilians, who had moved there to seek shelter from the violence in central Homs, were in danger.

UNICEF director Anthony Lake said clashes and rocket strikes in al-Waer meant the situation there had worsened in recent days and appealed to both the army and rebels to allow aid to get in.

"We call on all parties to facilitate immediate safe access to these families so we can provide life-saving assistance, and to allow those families currently trapped in al-Waer who wish to leave to do so in safety and in dignity," he said.

The more than two-year conflict in Syria has left at least 100,000 people dead and displaced millions of people.