Violence re-erupted across Yemen, killing at least 18 people in Sanaa and Taez, the second largest city.

Violence re-erupted across Yemen, killing at least 18 people in Sanaa and Taez, the second largest city.

In the flashpoint city of Taez, fifteen people were killed, including two gunmen, one civilian and a 13-year-old boy, and 12 others were wounded in the armed clashed that broke out early Wednesday between government forces and tribesmen who support a mass protest movement calling for President Ali Abdullah Saleh's resignation.

Residents and gunmen said pro-Saleh troops were targeting Taez neighbourhoods with heavy weapons, including mortars.

Late Tuesday, clashes were renewed in the capital between government troops and gunmen loyal to tribal chief Sheikh Sadeq al-Ahmar, killing at least three people, including two tribesmen and a policeman, said medical officials and the interior ministry.

At least seven others were wounded in the restive district, the scene of fierce clashes and shelling in recent weeks, said the medics.

The violence comes after a brief lull in bloodshed where government troops have been battling a nine-month uprising by pro-democracy activists, dissident soldiers, and tribal gunmen against Saleh's 33-year-rule.

International and regional mediators have failed to secure a Gulf-sponsored deal between Saleh and his opponents that would ensure a peaceful transition of power to the vice president until early elections for a new president.