Yemeni police have fired on anti-government protesters in the southern city of Taez, killing at least 12 people. The incident came amid an escalation of violence in several cities in Yemen.
Medics say several others were wounded in Monday's clashes. Witnesses say the protesters had tried to storm a provincial government building.
Meanwhile, The New York Times reports that the United States is dropping its support for President Ali Abdullah Saleh and is negotiating the terms of his departure.
Unidentified U.S. and Yemeni officials say the U.S. position changed more than a week ago, when the talks began.
The president has offered to step down, but only after new elections are held. His current term ends in 2013. He has been in power for 32 years.
A Yemeni official told the Times the negotiations center on a proposal in which Saleh would hand over power to a provisional government led by Vice President Abd al-Rab Mansur al-Hadi until new elections are held.
Violence raged, too, in the western city of Hudaida on Monday. Witnesses say police fired bullets and teargas at hundreds of protesters, wounding at least 50.
The violence comes a day after another demonstrator was reported killed Sunday in Taez, when police opened fire on anti-government protesters. Scores more were wounded.
Yemen has seen increasingly bloody protests against longtime ruler Saleh since late January. Saleh recently called for an end to the protests and said he is willing to discuss the peaceful transfer of power "according to the constitution."
Some information for this report was provided by AFP and Reuters.