At least 37 people have been killed in clashes in the Yemeni capital Sanaa between opposition protestors and government forces.
There was heavy fighting in the capital throughout the night.
Clashes between tribesmen loyal to Sheikh Sadiq al-Ahmar, who heads the powerful Hashid confederation, and security forces broke out in Sanaa yesterday ending a truce announced on Friday.
The government of veteran President Ali Abdullah Saleh has accused Mr Ahmar's fighters of breaking the truce.
The defence ministry's website said that his tribesmen had seized both the headquarters of the ruling General People's Congress and the main offices of the water utility.
But sources close to Mr Ahmar said President Saleh's forces were to blame as they had opened fire on the tribal leader's compound in the north of the capital.
