UN official describes Syria as 'in a state of civil war'
The main opposition group in Syria has struck a deal with insurgents calling themselves the Free Syrian Army, to work together against the government of President Assad.
The opposition Syrian National Council said the insurgents, many of them army deserters, had promised to use force only to protect civilians.
The senior UN official for Human Rights, Navi Pillay, has said the numbers of soldiers taking up arms against the government is growing.
She said Syria was in a state of civil war and more than 4,000 people had already been killed.
Jonathan Head reports.