Reports from Bahrain say that security forces launched an attack on the camp at Pearl Roundabout early this morning and cleared it of protesters (photographs here).

Helicopters were reported overhead and tents were set on fire. It is unclear whether the attack involved any of the Saudi forces who entered Bahrain on Monday. Tear gas was reportedly used.

At present, details are scarce, but the BBC has a report here. Below is another picture posted on yfrog.

Posted by Brian Whitaker, 16 March 2011, 05.30 GMT.

UPDATE, 08.00 GMT: Writing about this morning's events for the Guardian's website, Martin Chulov says:

Gunfire was heard throughout the capital and at least five helicopters were circling scenes of clashes, amid widespread panic on the streets below.

Riot police entered Manama's Salmaniya medical centre for the first time since the demonstrations began and doctors reported they were being prevented from reaching the hospital and treating patients inside. The police were also preventing casualties from reaching the facility. By 8am, they had closed its main gate and stationed forces outside.