Beirut: A French photojournalist and a prominent American war correspondent working for a British newspaper were killed Wednesday by Syrian shelling of the opposition stronghold Homs as President Bashar Al Assad's regime escalated its attacks on rebel bases by strafing from helicopter gunships, activists said.

Weeks of withering barrages on the central city of Homs have failed to drive out opposition factions that include rebel soldiers who fled Al Assad's forces.

Hundreds have died in the siege and the latest deaths further galvanised international pressure on Assad, who appears intent on widening his military crackdowns despite the risk of pushing Syria toward full-scale civil war.

'Regime must go'

"That's enough now, the regime must go," said French President Nicolas Sarkozy after his government confirmed the journalists' deaths.

French spokeswoman Valerie Pecresse identified those killed as French photojournalist Remi Ochlik and American reporter Marie Colvin, who was working for Britain's Sunday Times.

France's Foreign Minister, Alain Juppe, said the attacks show the "increasingly intolerable repression" by Syrian forces.

French Communication Minister Frederic Mitterrand said of the journalists killed: "It's abominable. Plus, they were being chased when they were trying to flee the bombings."

Syrian activists said at least two other Western journalists were injured in Wednesday's shelling, which claimed at least 13 lives.

The Syrian military has intensified its attacks on Homs in the past few days, aiming to retake rebel-held neighborhoods that have become powerful symbols of resistance to Al Assad's rule.

Rebel pockets

For the government in Damascus, Homs is a critical battleground to maintain its control of Syria's third-largest city and keep more rebel pockets from growing elsewhere.

In the northwestern restive province of Idlib, the Britain-based Syrian Observatory for Human Rights claimed that Syrian army helicopters fitted with machine guns opened fire on the village of Ifis. Idlib is a main base of the rebel Free Syrian Army.

Another opposition group, the Local Coordination Committees, said troops conducted raids in the Damascus district of Mazzeh district and the suburb Jobar, where dozens of people were detained. In Jobar, the group said troops broke doors of homes and shops and set up checkpoints.

Thousands killed

The Obama administration opened the door slightly Tuesday to international military assistance for Syria's rebels, with officials saying new tactics may have to be explored if al Assad continues to defy pressure to halt a brutal crackdown on dissenters that has raged for 11 months and killed thousands.

The White House and State Department said they still hope for a political solution. But faced with the daily onslaught by the Al Assad regime against Syrian civilians, officials dropped the administration's previous strident opposition to arming anti-regime forces.

It remained unclear, though, what, if any, role the U.S. might play in providing such aid.

A Homs-based activist, Omar Shaker, said the journalists were killed when several rockets hit a garden of a house used by activists and journalists in the besieged Homs neighborhood of Baba Amr, which has come under weeks of heavy bombardment by forces from Al Assad's regime.

At least 13 people were killed in Wednesday's shelling, including the journalists, activists said.

The UN estimates that 5,400 people have been killed in repression by the regime of President Bashar Assad against a popular uprising that began 11 months ago. Syrian activists, however, put the death toll at more than 7,300.

He added that intense Syrian troops shelling with tanks and artilleries began at 6:30 a.m. and was continuing hours later. He said the apartment used by journalists was hit around 10am.

Flak jacket

An amateur video posted online by activist showed what they claimed were bodies of two people in the middle of a heavily damaged house. It said they were of the journalists. One of the dead was wearing what appeared to be a flak jacket.

Many foreign journalists have been sneaking into Syria illegally in the past months with the help of smugglers from Lebanon and Turkey. Although the Syrian government has allowed some journalists into the country their movement is tightly controlled by Information Ministry minders.

Colvin, from Oyster Bay, New York, was in her 50s and a veteran foreign correspondent for Britain's Sunday Times for the past two decades. She was instantly recognizable for an eye patch worn after being injured covering conflicts in Sri Lanka in 2001.

Colvin said she would not "hang up my flak jacket" even after the eye injury.

"So, was I stupid? Stupid I would feel writing a column about the dinner party I went to last night," she wrote in the Sunday Times after the attack. "Equally, I'd rather be in that middle ground between a desk job and getting shot, no offense to desk jobs.

Red Cross

In Geneva, the International Red Cross said it was holding talks with members of the opposition Syrian National Council. The ICRC called Tuesday for a daily two-hour halt to fighting in Syria so it can bring emergency aid to affected areas and evacuate the wounded and sick.

Head of ICRI operations for the Middle East, Beatrice Megevand-Roggo, told The Associated Press on Tuesday that the ICRC had almost no contacts with opposition figures inside Syria.

Sniper

The journalists' deaths came a day after a Syrian sniper shot dead Rami Al Sayyed, a prominent activist in Baba Amr who was famous for posting online videos, Shaker and the Local Coordination Committees activist group said.

On January 11, award-winning French TV reporter Gilles Jacquier was killed in Homs.

The 43-year-old correspondent for France-2 Television was the first Western journalist to die since the uprising began in March. Syrian authorities have said he was killed in a grenade attack carried out by opposition forces — a claim questioned by the French government, human rights groups and the Syrian opposition.

Last week, New York Times correspondent Anthony Shadid died of an apparent asthma attack in Syria after he snuck in to cover the conflict.