Yemen’s Ali Abdullah Saleh is reportedly in negotiations to end his Presidency. According to the New York Times, the US Embassy and Saudi Arabia are keeping watch on these negotiations, which are being carried out between Saleh and multiple factions and interest groups. If completed, Saleh would be the third Arab head of state this year to be forced to step down by a protest movement, joining Zine El Abidine Ben Ali in Tunisia and Hosni Mubarak in Egypt.

No deal has yet been reached, but the protesters plan to put more pressure on Saleh today after Friday prayers with a large rally outside Sanaa University, called the “Day of Departure.” The capital has become a virtual tent city, with pro-democracy activists packing the streets and calling for the President’s removal.

On Thursday evening, hundreds of once pro-Saleh tribesmen arrived in what is known as “Change Square” from Marib Province and marched through the boisterous crowds, the latest group to announce their defection to the populist revolution. “Welcome, Welcome,” an activist yelled over loudspeakers.

Pressure is building, seemingly from every corner of Yemen, for Saleh to step down immediately, even as the United States and its allies appear to favor a more gradual transition of power in a fragile nation beset by multiple emergencies, including a potent al-Qaeda presence.

In a positive sign, military leaders who defected to the opposition begged off any elevation to power for themselves. Gen. Ali Mohsen al-Ahmar said he wanted to live the rest of his life in peace and tranquility, and added that “Military rule in the Arab world is outdated.”

Waves of diplomats, cabinet ministers, military generals and tribal leaders – including most recently the respected leader of the largest tribe, Sheik Sinan Abu Lohoum – have disassociated themselves from Saleh rapidly since the violent attempt at repression last week which killed dozens of peaceful protesters. Yemeni society reacted to the violence by stepping up calls for Saleh’s removal and hardening their stance on this point.

The student leaders, which have led this movement in Yemen from the beginning, laid out a list of demands Thursday, calling for a new Constitution, a dissolution of Parliament and local councils, elimination of the Yemeni security agencies and the immediate resignation of President Saleh. This was rejected by Saleh on state-run TV.

Saleh rejected the offer, lashing out instead out at the protesters threatening his 32-year rule.

“Even if we entered with them now into an understanding, the situation will be worse than it is now,” Saleh said of the opposition. “We will cling to constitutional legitimacy and we will preserve the security, independence and safety of the Yemeni republic with all means possible.”

But even as he rejects offers in public, Saleh is negotiating the terms of his exit in private.