SANAA, Oct 17 - At least eight people were killed in Yemen's capital Sanaa in overnight clashes between government forces and fighters allied with activists demanding an end to Ali Abdullah Saleh's 33 years in office, witnesses said on Monday.
Witnesses said six civilians were among those killed in the fighting between government troops on one side, and fighters loyal to tribal leader Sheikh Sadeq al-Ahmar on the other. Ahmar's fighters are backed by a breakaway army unit led by a general from the same tribe, Ali Mohsen al-Ahmar.
A shell killed three people when it landed near a field hospital set up at "Change Square," where thousands of protesters have camped for months demanding Saleh step down, witnesses said.
Violence in Yemen has surged since Saturday as U.N. Security Council members consider a resolution expected to urge Saleh to step down under a peace plan hammered out by neighboring Gulf states.
Saleh has remained in office despite ten months of mass protests against his rule inspired by demonstrations across the Arab world. Opposition to him has turned increasingly violent and organized, threatening to plunge the country into all-out civil war.
Yemen, the Arab world's poorest country, also faces tribal conflict, violence from a strong regional al Qaeda wing, separatism in the south and sectarian conflict in the north.
Saleh, who says he is ready to step down but wants to ensure that control of the country is put in safe hands, has said he is relying on support from Russia and China to stop moves to force him to step down.
Speaking at a meeting of his security and military chiefs in Sanaa, he said Western countries with permanent seats on the Security Council had based their decisions on information gathered solely from the opposition.
The United States and Saudi Arabia, which shares a long and porous border with Yemen, fear that al Qaeda is taking advantage of the political vacuum to expand its influence.
Islamist militants linked to al Qaeda captured large swathes of southern Abyan province, including regional capital Zinjibar, earlier this year. The Yemeni army last month drove the militants out of Zinjibar, east of a strategic shipping strait through which some 3 million barrels of oil pass daily.
Tribal sources said at least five people were killed late on Sunday when tribesmen ambushed members of al Qaeda in Zinjibar. Local officials said security forces captured three suspected militants, including a Saudi national, in the incident.
"The tribal fighters ambushed the militants as they were transporting military supplies late on Sunday. The two sides fought, leading to the deaths of four militants and one tribesman," a tribal source told Reuters.
The tribesmen also destroyed a D-130 tank which militants had seized from the Yemeni army when captured Zinjibar earlier this year, the source said.
Suspected militants blew up Yemen's gas pipeline last week after an air strike killed a top al Qaeda leader and a number of other militants in southern Yemen.
(Reporting by Mohamed Sudam in Sanaa and Mohammed Mukhashaf in Aden, Writing by Nour Merza; Editing by Sami Aboudi and Peter Graff)