STRUGGLE: Residents attend the funeral of people whom protesters say were killed by forces loyal to Syria's President Bashar al-Assad, in Deraa yesterday. Picture: REUTERS

GUNMEN stormed a pro-government Syrian TV channel headquarters yesterday, bombing buildings and shooting dead three employees, state media said, in one of the boldest attacks yet on a symbol of the authoritarian state.

President Bashar al-Assad declared late on Tuesday that his country was "at war". US intelligence officials said the Syrian regime was "holding fairly firm" and digging in for a long struggle against rebel forces, who are getting stronger.

The dawn attack on Ikhbariya TV's offices, 20km south of the capital, as well as overnight fighting on the outskirts of Damascus, showed 16 months of violence now rapidly encroaching on the capital.

Ikhbariya resumed broadcasting shortly after the attack, displaying bullet holes in its building and blood on the floor. One building had been almost completely destroyed.

The Syrian media are tightly regulated by the ministry of information. Although Ikhbariya is privately owned, opponents of Mr al-Assad say it is a government mouthpiece.

"We live in a real state of war from all angles," he told a cabinet he appointed on Tuesday night, in a speech broadcast on state TV. "When we are in a war, all policies and all sides and all sectors need to be directed at winning this war."

The declaration marks a change of rhetoric from Mr al-Assad, who had long dismissed the uprising against him as the work of scattered militants in "terrorist gangs" funded from abroad.

The rambling speech - Mr al-Assad also commented on subjects such as renewable energy - left little room for compromise. He denounced the West, which "takes and never gives, and this has been proven at every stage".

The United Nations (UN) accuses Syrian forces of killing more than 10000 people during the conflict, which began with a popular uprising and has built up into an armed insurgency, which is threatening to destabilise the region, against four decades of rule by Mr al-Assad and his father. Activists said the figure could be closer to 15000.

Despite some military defections Mr al-Assad's inner circle remains cohesive and the war is still likely to be a drawn-out struggle, senior US intelligence officials said, in an assessment dimming any US hopes that Mr al-Assad will fall soon of his own accord.

"Our overall assessment ... would be that we are still seeing the military regime forces fairly cohesive, they've learned some lessons over the last year-and-a-half about how to deal with this kind of insurgency," an official said. The insurgency was also getting stronger, he said.

"Both sides seem to be girding for a long struggle. Our sense is that the regime still believes it can ultimately prevail or at least appears determined to try to prevail and the opposition at the same time seems to be preparing for a long fight."

Despite the deterioration in Syria, so far there has been no sign of an appetite for western intervention.

Video published by activists on Tuesday recorded gunfire and explosions in suburbs of Damascus. Syria's state news agency Sana said "armed terrorist groups" had blocked the old road from Damascus to Beirut this week.

The UN peacekeeping chief said it was too dangerous for a UN observer team, which suspended operations this month, to resume monitoring a ceasefire at the heart of a peace plan by international envoy Kofi Annan. The truce is on paper only. Mr Annan called for a meeting of Friends of Syria last Saturday.

The Syrian Observatory for Human Rights, which compiles reports from rebels, said 135 people were killed on Tuesday, making it one of the bloodiest days of the conflict.

The daily death toll in recent days has been about 100. The observatory reported battles near the headquarters of the Republican Guard in Qudsiya, and in Damascus suburbs of al-Hama and Mashrou' Dumar, just 9km from the capital.

In neighbouring Turkey, Prime Minister Tayyip Erdogan ordered his armed forces to react to any threat from Syria near the border, after Syrian forces shot down a Turkish warplane on Friday off the Mediterranean coast. North Atlantic Treaty Organisation-member Turkey is the base for the rebel Free Syrian Army and shelters an estimated 30000 refugees.