SANAA, Yemen (AP) -- Witnesses say police have opened fire to break up an anti-government protest in Yemen, and security officials say one protester has been critically wounded.
It was not immediately clear whether the police were using live ammunition or rubber bullets.
The security officials say two others demonstrators were also wounded in the eastern town of Mukalla, but no details were immediately available.
The protest in Mukalla was one of several anti-government demonstrations across Yemen Thursday. Tens of thousands joined in the protests, chanting "down, down with the regime."
The marches were among the largest yet against President Ali Abdullah Saleh, a key U.S. ally in the fight against al-Qaida. Earlier this week, the president promised not to extend his term beyond 2013 in an attempt to defuse calls for his ouster.