The govFernment and the supporters of Sadiq al-Ahmar, the leader of the powerful Hashad tribe, accused each other of breaking the truce and bringing the embattled country closer to a civil war.
"The ceasefire agreement has ended," a government official told Reuters when asked whether an overnight exchange of fire between the two sides had broken the fragile truce.
Militants loyal to al-Ahmar regained control of Yemen's ruling party building in the Hasaba district of the capital Sanaa where much of the fighting took place.
The violence, pitting Saleh loyalist forces against Hashed tribesmen has been the bloodiest since pro-democracy unrest erupted in January and was caused by Saleh's refusal to sign a power transfer deal.
Copyright Reuters, 2011