As protests enter their third month in Yemen, the United States has abandoned its longtime support of President Ali Abdullah Saleh, an ally in the region for counter-terrorism operations. The news comes as security forces in the country reportedly massacred 15 anti-government protesters.

Until last week, the U.S. had supported Saleh "because he was considered a critical ally in fighting the Yemeni branch of Al Qaeda," the New York Times reported. But now the Obama administration has deemed Saleh's rule "untenable," and work is underway to ease him out of power.

[The] negotiations now center on a proposal for Mr. Saleh to hand over power to a provisional government led by his vice president until new elections are held. That principle “is not in dispute,” the Yemeni official said, only the timing and mechanism for how he would depart.

It does remain in dispute among the student-led protesters, however, who have rejected any proposal that would give power to a leading official of the Saleh government.

While those behind-the-scenes talks continue, thousands of anti-government protesters marched through the city of Taiz on Monday resulting in a familiar violent response by government forces. The Times of India reports:

Clashes broke out as the marchers passed the Governor's headquarters, where troops barred their way baton charging them, bursting teargas and then opened fire, killing 15 people on the spot.

"At least 15 people were killed by live bullets and hundreds lay wounded as troops on nearby rooftops opened fire with live ammunition," opposition activists said.

A week after government-linked gunmen killed some 50 protesters on March 18, it was reported that the president would step down as early as March 26. But that date came and went and Saleh has stayed in power. Now, officials are discussing safe passage for Saleh and the installation of a new, hopefully democratic, leadership. Still, the U.S. government is keeping its priorities straight, according to the Times: "For Washington, the key to his departure would be arranging a transfer of power that would enable the counterterrorism operation in Yemen to continue."