Human rights activists and residents of Homs, Syria's third largest city, are reporting intense gunfire as security forces conduct raids and arrests.

Security forces were said to be "shooting randomly" and there are reports of more deaths and arrests as Syrian forces move in.

Activists say the army has used tanks to shell densely populated parts of the city of Homs.

They say at least 40 people have been killed in the city in the last week. That number is expected to rise.

Al Jazeera is not allowed to report in Syria, and must rely on pictures posted, often at great risk, on sites like YouTube.

Al Jazeera's Tarek Bazley reports.