Yassin Saeed Noman, head of the Joint Meetings Parties coalition, and other leaders came to the protest encampment for the first time, The New York Times reported. The group included both socialists like Noman as well as Islamists.
"When the people come to the square of change, there is no voice louder than theirs," Noman said, addressing several hundred people. "You are the generation that will bring the revolution to Yemen."
The appearance of political leaders and the resignation of a number of top officials followed the killings Friday of at least 45 people. About 200 were wounded when security forces fired into crowds of demonstrators and snipers fired from rooftops.
The state-run SABA news agency said at least three senior government officials quit and distanced themselves from the ruling General People's Congress party after the bloodshed in Sanaa. The Times said the resignations included the minister for tourism, the ambassador to Lebanon, Saba's editor in chief and the top editors of two state-run newspapers.
President Ali Abdullah Saleh declared a state of emergency Friday as an estimated 1.5 million people calling for his resignation gathered in Sanaa and other cities.
Saleh called an emergency news conference Friday night and denied government troops had killed anyone and alleged protesters had turned on one another.
Hours later, the Ministry of Information announced it had ordered two correspondents for the Arabic TV network al-Jazeera out of the country for calling Friday's government response a massacre.
Late Friday, the United Nations issued a condemnation of the government's use of force against its citizens.