SYRIAN rebels said they had captured an air defence base with a cache of missiles outside Damascus, a rare advance on the city after a series of opposition setbacks in the capital.

Rebel forces overran the base in the eastern Gouta area, a few miles east of Damascus, as about 180 people were killed in violence across the country, including 48 government soldiers, the British-based Syrian Observatory for Human Rights said.

In New York, the UN Security Council condemned a cross-border mortar attack by Syrian forces that hit a Turkish village. It demanded that such violations of international law stop immediately.

Turkish artillery had bombarded Syrian positions earlier in the week but the border area appeared to be quiet yesterday.

The incident underscored how the conflict, now in its 19th month, could flare across the region, while the continued fighting showed the situation inside Syria was only getting more serious.

Meanwhile, Syrian warplanes and artillery have pounded the central city of Homs, subjecting the former rebel stronghold to its worst bombardment in months, activists said.

The reported bombardment by tanks, mortars and aircraft comes alongside a push by government forces on the embattled northern city of Aleppo.

Homs has been one of the flashpoints of the uprising against president Bashar al Assad's regime. The focus of fighting has shifted to other areas in recent months, including Aleppo, since a government offensive against rebel strongholds in Homs ended in April.

The Syrian Observatory for Human Rights said yesterday's attack was the worst Homs had seen in five months. The observatory, which relies on a network of activists on the ground, said the city's Khaldiya neighbourhood had been heavily bombarded.

More than 30,000 people have been killed in the uprising, which began with peaceful street protests but is now a full-scale civil war.

A video of the assault on the airbase showed dozens of rebels dressed in army fatigues celebrating as black smoke rose from a military installation behind them.

A middle-aged man holding a rifle says the attack was carried out by a rebel battalion from the town of Douma. The video also showed rebels at a weapons cache that included what appeared to be part of a surface-to-air missile. When rebels have captured army bases in other parts of the country, war planes have bombed the sites shortly afterwards.

Although there has been frequent fighting in the Damascus suburbs, rebel forces have been unable to hold areas for long in the face of superior government artillery and air power.

However, the rebels have staged devastating bomb attacks on government and military offices in the heart of the city.

Meanwhile, Turkey has made clear it is ready to launch retaliatory strikes again if the war spills over the border, but it has also said it will act under international law and in co-ordination with other foreign powers.

This week's cross-border violence was the most serious so far in the conflict.

Five Turkish civilians were killed in the south-eastern town of Akcakale by the Syrian mortar attack. The Turkish salvoes killed several Syrian soldiers.