SANAA: Tens of thousands are demonstrating in Yemen, demanding that their longtime president be put on trial for the killing of hundreds of unarmed protesters since pro-democracy protests began 10 months ago.

Friday's gatherings comes as President Ali Abdullah Saleh is due to hand over power to his deputy in exchange for immunity from prosecution.

Many protesters have rejected the power transfer deal, which was brokered by Gulf Arab nations and supported by the United States, because it doesn't include far-reaching political changes or allow for Saleh to be tried.

A few thousand Saleh supporters of held a counter-rally in the capital, calling the power transfer deal unconstitutional.

Al-Qaida-linked militants in Yemen have taken advantage of the political turmoil to strengthen their positions in the country's south.