Tribesmen in Yemen opposed to President Ali Abdullah Saleh have said they stormed a military base on the outskirts of the capital and stolen weapons.

Hameed Asim, a leader of the tribesmen who skirmished with troops from the Republican Guard led by Saleh's son, said tribal fighters killed several troops and lost seven of their own in a raid on the base in Arhab region north of Sanaa before withdrawing.

The attack was the latest in a series of running battles between tribesmen and forces backing Saleh, who is clinging to power despite 10 months of protest demanding his overthrow and a slide toward civil war on the borders of Saudi Arabia.

Meanwhile, youth activists are concerned that their protest movement is being hijacked by rival military factions and tribes.

Al Jazeera's special correspondent, who we are not naming for her own safety, reports from Sanaa.