SANA'A // Demonstrators fled a square in Yemen's capital today as security forces attacked pro-opposition troops led by the dissident General Ali Mohsen al Ahmar who were protecting the sit-in protest.
Gunfire rang out in Sana'a, raising fears among the protesters in University Square, dubbed "Change Square" after it became the centre of anti-regime demonstrations in February, said an AFP correspondent.
Less than 2,000 people were still at the square where at least 10,000 demonstrators used to gather daily since the eruption of the protests calling for the overthrow of President Ali Abdullah Saleh.
Fears had risen after government shelling yesterday targeted General Ahmar's troops, stationed near the square to protect the demonstrators, according to his spokesman, Askar Zueiyl.
The forces were "targeted by an artillery shell and several soldiers were killed," Mr Zueiyl told AFP.
However, "the numbers and identities of those killed could not be verified as their body parts were scattered dozens of metres from the area and some of them were burned," he said.
Tribesmen loyal to the powerful opposition chieftain Sheikh Sadiq al Ahmar have been locked in gunbattles in Sanaa with government forces that have killed at least 44 people since Monday, according to an AFP tally based on reports.
Clashes between the security forces and Sheikh al Ahmar's followers broke out in the capital after Mr Saleh refused to sign a GCC-brokered deal that would see him leave office within 30 days.
The tribesmen occupied public buildings, including the state news agency Saba and the national airline Yemenia building and have tried to storm the interior ministry headquarters, according to witnesses and a high-ranking Yemen official.
Protesters today took to the streets of Taez and Ibb, south of Sana'a, and in the Red Sea city of Hudaydah, chanting against the violence in Sana'a.
"Our revolt is peaceful, we will not be dragged into civil war," their banners read.
Since late January, security forces and armed Saleh supporters have mounted a bloody crackdown on protests demanding his departure, killing at least 181 people, according to a toll compiled from reports by activists and medics.
The latest fighting came despite an appeal on Tuesday by President Saleh for supporters of Sheikh al Ahmar, who heads the powerful Hashid tribal federation, to "cease their aggression on security forces."
The president, who has said the situation could deteriorate into civil war, also called on the tribesmen to "withdraw their armed partisans from public buildings and facilities," the defence ministry's 26sep.net news website said, adding that security forces would observe a ceasefire.
Today President Barack Obama reiterated his call for Saleh to leave office.
"We call upon President Saleh to move immediately on his commitment to transfer power," Mr Obama said, in a joint press conference with the British prime minister, David Cameron, in London.
A number of residents on Wednesday were seen fleeing Sana'a southwards, hoping to escape the fighting as well as electricity and water shortages, an AFP correspondent said.
Those attempting to head north ran into Republican Guards checkpoints and were advised that they may not be allowed to return to Sanaa. The area north of the capital is a stronghold of Ahmar's Hashid federation.
Access to Al Hasaba neighbourhood has been cut by cement blocks and burning tyres placed in the streets.
Sheikh al Ahmar in March pledged his support for the opposition, which since January, supported by widespread street protests inspired by popular uprisings in Tunisia and Egypt, has been demanding President Saleh's departure.
The Gulf Cooperation Council yesterday demanded an immediate halt to the bloody clashes between regime supporters and Sheikh al Ahmar's clansmen.
"The fighting in Sanaa during the past two days is a source of concern for the GCC who fear that it may spread," said the GCC's secretary-general, Abdullatif al Zayani.
Sources close to Sheikh al Ahmar said the fighting had broken out on Monday after security forces tried to deploy around his residence and his gunmen retaliated.
A Yemen security official however said the gunmen broke into a nearby school and police responded.
The conflicting accounts could not be independently verified.
One of the 10 sons of Sheikh Abdullah al Ahmar, who was until his death President Saleh's main ally, Sheikh al Ahmar is capable of rallying thousands of armed supporters, tribal sources say.
Yemen has an estimated 60 million firearms in private hands, roughly three for every citizen.
The country's opposition promised on Monday to step up street protests, while insisting on efforts to avoid violence.