Demonstrators massed in Sanaa on Friday demanding that Yemeni President Ali Abdullah Saleh be put on trial over his regime's bloody repression of their opposition movement.

"Let the world know that Saleh must be tried" and "No immunity for the executor," the protesters, who were mostly youths, chanted as they marched in a street near Change Square after the main weekly Muslim prayers.

But protests were relatively subdued on the eve of the swearing in of a national unity government tasked with overseeing a transition period until Saleh's departure in February in line with a Gulf-brokered deal.

The power transfer accord means "we have achieved one of the objectives of the revolution: the fall of the nepotistic and totalitarian regime," Hamza Kamali, a youth protest coordinator, told AFP.

"We will stand by the national unity government if it meets our demands," including the establishment of a democratic state, the restructuring of the army and security forces, as well as an independent judiciary, Kamali added.

One of the protesters, Muyin al-Dhaley, said that they supported the newly named government because "the people are tired of years of suffering."

"But the youth will continue their sit-ins overthrow the government if it doesn't work towards the creation of a modern state," he told AFP.

Mohammed Meftah, another young demonstrator, warned: "The youths will only stop their sit-in protests once all those responsible for spilling Yemeni blood have faced justice."

Saleh's General People's Congress party ordered its supporters not to stage any rival rallies after Friday prayers, as they have done since democracy protests erupted in January.

Tens of thousands of Yemenis marched the streets of Sanaa on Thursday, chanting "no partnership with murderers," in reference to former regime loyalists that have been appointed to the newly formed unity government.

Hundreds of Yemenis have been killed and thousands more wounded in more than 11 months of demonstrations that continue despite the Gulf-sponsored power transfer deal to ensure Saleh's ouster.

The protesters have also expressed dismay with the formal opposition for signing the Gulf Cooperation Council plan which promises Saleh immunity from prosecution for alleged crimes committed against Yemenis since the uprising.