Another explosion tears through the Syrian city of Homs.

This amateur video shows what activists say is a government artillery strike on a rebel-held residential neighbourhood.

Reuters cannot independently verify the content of this video, but it is one of several to emerge in recent days reportedly showing widespread destruction in Homs.

The city is at the centre of an uprising against long-time Syrian president Bashar al-Assad.

Activists say hundreds of civilians have died in four weeks of shelling by Syrian security forces.

The clashes triggered fresh condemnation from Turkish foreign minister Ahmet Davutoglu.

(SOUNDBITE) (Turkish) TURKISH FOREIGN MINISTER AHMET DAVUTOGLU SAYING:

"The Syrian regime should immediately stop the violence upfront; withdraw its army from all locations and open its doors to the international community. How can we expect a fair referendum and free elections in a country where even journalists are being killed?"

Meanwhile, the opposition Free Syrian Army claimed a rare victory.

This video purports to show two government tanks engulfed in flames, and activists say rebels took over a nearby military post.

The fighting has sparked a humanitarian crisis in Homs, and Syrian state tv reported the Red Crescent has been allowed into the city to rescue scores of injured.

Andrew Raven, Reuters.