With some fifty people shot dead in protests in Yemen's capital of Sanaa last Friday, security forces are gathering in force to meet this Friday's protests, Reuters reports.

This Friday's protest, during which protesters will continue to call for the immediate resignation of President Ali Abdullah Saleh, who has ruled the fractious, tribal county of Yemen since 1978, are expected to the be the largest yet. Protesters also want constitutional changes, the dissolution of the internal security services, and resignation of the government.

"Friday will be the 'Friday of the March Forward,' with hundreds of thousands of people," opposition spokesman Mohamed Qahtan told Al Jazeera on Wednesday, addressing the Yemeni leader. "We will arrive where you are and we will remove you,"

Weeks ago, Saleh offered to begin constitutional reform and step down within a year, but opposition leaders rejected his overture.

On Wednesday, in the wake of last Friday's bloodbath, Yemen's parliment passed sweeping emergency laws granting far reaching powers to the security services to detain suspects and prevent demonstrations. But as of Friday, both the government and opposition have set up check points in Sanaa and fears of confrontation run high as groups of armed men rove the streets.

Saleh has warned continued unrest could plunge Yemen into civil war.

"They call for the regime going and that means chaos and destruction," Saleh told a gathering of tribal leaders on Sunday. "Yes, the regime can go, but via democratic means, and that involves the ballot box and elections. Coups are rejected."

Western Fears

Seven weeks of street protests against Saleh's 32-year rule has raised alarm in Western capitals at the specter of an impoverished country a strategically critical region plunging into sectarian chaos.

Yemen does not have a unified polity and it is unclear whether opposition groups can form a cohesive government in the power vacuum Western and Gulf-Arab-backed Saleh's resignation would create.

Yemen has long had a separatist movement who complain of neglect in the south, tensions with an perennially rebellious Shiite minority in the north, and has become a breeding ground for Al Qaeda.

Yemen borders the world's biggest oil exporter, Saudi Arabia, and major shipping routes. In the past two years, Al Qaeda cells have used Yemen as a staging ground for attempted terrorist attacks on Saudi Arabia and the United States.

Loyalist Defections

Defections including generals, tribal leaders, diplomats and ministers, gained momentum after last Friday's bloodbath, causing the deaths of 52 people. Saleh sacked his cabinet and declared a state of emergency, but the bloodshed has brought protests to a fervered, near explosive pitch.

On Wednesday, protesters carried placards saying "No to emergency rule, you butcher!"

Shirts were on sale saying, "I am a future martyr."

Some soldiers were wearing red roses to demonstrate support for what is being termed the 'youth revolution.'

"We are its protection," said one soldier, with a plastic rose affixed to his rifle.

Defections among the ruling elite include senior military commanders, notably General Ali Mohsen, commander of the northwest military zone and Saleh's kinsman from the al-Ahmar clan. But not everyone in the opposition is happy to have him.

"We see Ali Mohsen's joining us as a corruption of the revolution," Abdullah Hussein al-Dailami told the Associated Press. "The revolution is not against an individual but against a system."