Thousands of demonstrators in Taiz shouted anti-Saleh slogans and demanded the postponement of school exams, while protests erupted elsewhere in the impoverished country that Saleh has ruled for nearly 33 years.

Clashes were reported in the Red Sea port city of Hudaida, where security forces stormed a university campus to break up protests, wounding six, activists said. Six more people were wounded in clashes in Dhamar province, south of Sanaa.

The unrest has included workers' strikes. The Canadian oil company Nexen Inc, said it halted production at its Yemen operations because of a labor disruption.

Security forces, some in armoured vehicles, moved in to disperse the protest, wounding at least 80 protesters in the industrial city.

The latest violence came as the Arabian Peninsula country's main opposition group awaited word on whether Gulf Arab states could revive a deal to edge Saleh out of power within a month.

A shopkeeper who ran a small kiosk was killed by a stray bullet, and two protesters were also shot dead amid heavy gunfire as security forces tried to disperse a protest near the education ministry, a doctor treating the wounded said.

A third protester later died of his wounds, the doctor said.

Yemen produces around 280,000 barrels per day of oil, including about 110,000 barrels of light crude, which is in short supply globally after the loss of Libyan output in February.