By Mohamed Sudam and Cynthia Johnston
SANAA (Reuters) - Top generals, ambassadors and some tribes threw their support behind Yemen's anti-government protesters on Monday in a major blow to President Ali Abdullah Saleh as he tries to survive growing demands for his immediate departure.
The president, a perennial survivor who has stayed in power for 32 years throughout a civil war, numerous uprisings and militant campaigns, has seen a string of allies break ranks with him in recent days.
On Friday snipers killed 52 anti-government protesters in Sanaa, prompting Saleh to sack his cabinet and declare a state of emergency for 30 days that restricts freedom of movement and the right to gather and gives police more power of arrest.
But the televised announcement of defection by General Ali Mohsen, a powerful figure close to Saleh, will be a major setback to Saleh.
"We announce our peaceful support for the peaceful revolution of the youth and their demands and we carry out our duty ... in ensuring security and stability in the capital," Mohsen, commander of the northwest military zone, said on Al Jazeera television.
"Yemen today faces a serious crisis ... as a result of unconstitutional and illegal practices by the authorities, a policy of marginalization and absence of justice," Mohsen said.
"Repressing peaceful demonstrators in public areas around the country has led to a cycle of crises which is getting more complicated each day and pushing the country toward civil war."
Mohsen is a kinsman of Saleh from the influential al-Ahmar tribe, whose members hold many key positions in the state.
SALEH'S ALLIES BREAK RANKS
Two other generals announced their support for the protesters, according to Al Jazeera -- Mohammed Ali Mohsen al-Ahmar, commander of the eastern military section, and Hamid al-Qosheibi, commander of the Amran region.
Among other prominent officers voicing support for protesters was Abdullah Alaiwa, a former defense minister and adviser to the army staff, Al Jazeera said.
Two Yemeni ambassadors also resigned their posts in protest at the government's crackdown on protesters. They include Abdel-Wahhab Tawaf, Yemen's ambassador to Syria, and Mohammed al-Ahwal, Yemen's ambassador to Saudi Arabia.
"I am resigning after the massacre that happened at the Taghyir (Change) Square," Tawaf told Al Jazeera television.
Sheikh Sadeq al-Ahmar, leader of the Hashed tribal federation to which the Ahmar belong, also spoke on Arab satellite televisions of his support for the protest movement.
The governor and his deputy in Aden, a port city at the center of a secessionist movement in south Yemen, and the deputy speaker of parliament and several ruling party MPs were among others who expressed support on Monday for the protest movement.
Mourners buried some of the protesters shot dead after Muslim Friday prayers in the impoverished Arabian Peninsula state, where tens of thousands of people have protested for weeks against Saleh's three decade-old rule.
Saleh has already said he will not run for reelection in 2013 and proposed political reforms including a new constitution in an effort to end weeks of protests.
Western countries are concerned over the unrest since Yemen has been an ally against a wing of al Qaeda which has tried to mount attacks against the United States and crucial oil producer Saudi Arabia.
Yemen is seen as facing potential disintegration and collapse of central control.
(Additional reporting by Martina Fuchs and Firouz Sedarat in Dubai; Writing by Andrew Hammond; Editing by Andrew Roche)