Syrian President Bashar al-Assad's forces rained rockets and bombs down on opposition-held neighbourhoods of the city of Homs on Wednesday, reducing buildings to rubble and killing more than 80 people, including two Western journalists.

The barrages marked an intensification of a nearly three-week offensive to crush resistance in Homs, one of the focal points of a nationwide uprising against Assad's 11-year rule, and prompted further international condemnation.

More than 60 bodies, both rebel fighters and civilians, were recovered from one area of Homs' Babo Amro neighbourhood after an afternoon bombardment, adding to 21 killed earlier in the day, activists said.

Helicopters flew reconnaissance overhead then the bombardment started, Homs activist Abu Abei told Reuters.

Videos uploaded by opposition activists showed smashed buildings, deserted streets, and doctors treating wounded civilians in primitive conditions in Baba Amro, the main target of Assad's wrath.

President Assad wants to finish the Homs situation by Sunday to prepare for the constitutional referendum. Then he will turn to Idlib, a Lebanese official who is close to the Syrian government told Reuters in Beirut.

The devastation has caused outcry but Wednesday's carnage only showed how helpless Western powers are in their efforts to stop the bloodshed.

The United States, which so far has been against military intervention in Syria, hinted however that if a political solution to the crisis was impossible it might have to consider other options.

The worsening humanitarian situation in Homs and other embattled towns is bound to dominate Friends of Syria talks in Tunis on Friday involving the United States, European and Arab countries, Syria's neighbour Turkey and other nations clamouring for Assad to halt the bloodshed and relinquish power.

In an effort to bring relief to starving and bloodied civilians in Homs, the International Committee of the Red Cross was in talks with the Syrian government on Wednesday to arrange a pause in the fighting.

Russia, Assad's main arms supplier and seen as retaining some leverage over him, said it was seeking safe passage of aid convoys to civilians trapped in the violence. France also appealed to Assad to halt the onslaught to allow safe passage for aid.

U.N. humanitarian chief Valerie Amos will head to Syria soon in an attempt to secure access for aid workers seeking to deliver emergency relief to people trapped in the country's conflict zones, the United Nations said on Wednesday.

THAT'S ENOUGH

French President Nicolas Sarkozy called the deaths of the two journalists, French photographer Remi Ochlik and American Marie Colvin of Britain's Sunday Times, an assassination and said the Assad era had to end.

That's enough now, Sarkozy said. This regime must go and there is no reason that Syrians don't have the right to live their lives and choose their destiny freely. If journalists were not there, the massacres would be a lot worse.

The two foreign journalists were killed when the house in which they were staying after sneaking over the Lebanese border into Homs was hit by rockets.

The last despatch from Colvin -- a veteran war reporter who wore a trademark black eye-patch since being wounded in Sri Lanka in 2001 -- described the misery inside Babo Amro.

Women and children were crammed together into a basement, huddled in fear and a two-year-old child had died in front of her, she reported on British radio.

The Syrian Network for Human Rights said government forces killed a total of more than 80 civilians in Homs on Wednesday, mostly in bombardments on Baba Amro, a Sunni Muslim district opposed to Syria's Alawite ruling class.

Several hundred people have been killed in the daily bombardments by the besieging forces using artillery, rockets, sniper fire and Soviet-built T-72 tanks.

Residents fear Assad will subject the city to the same treatment as his late father Hafez inflicted on the rebellious town of Hama 30 years ago, when 10,000 were killed.

Ground forces have held off from entering opposition areas as fighters allied to the opposition are ready to take them on.

The army is preventing medical supplies from going in and electricity is cut off 15 hours a day, activists say. Hospitals, schools and most workplace and shops are shut and government offices have also closed.

As the Lebanese official explained it, Assad wants to batter Homs into submission before a referendum this Sunday on a new constitution leading to multi-party elections as a way to resolve the crisis.

His plan has the support of his allies Russia and China but Western powers have dismissed it as a joke under the present circumstances and the Syrian opposition has called for a boycott.

RED CROSS APPEAL

The ICRC issued a public appeal on Tuesday to Syrian authorities and rebels to agree on a two-hour truce each day to allow life-saving supplies to reach civilians and to evacuate the growing number of wounded from Homs and elsewhere.

ICRC spokeswoman Carla Hadda said she was unable to say if and when a deal might be clinched.

The situation is difficult and we are worried it is deteriorating, she told Reuters on Wednesday. Everybody is focused on Homs but we shouldn't turn a blind eye to what is happening in other areas.

Army bombardments on the town of Khan Sheikhoun, north of Homs on the Damascus-Aleppo highway in Idlib province, killed two people on Wednesday, the London-based Syrian Network said.

Elsewhere in Idlib, seven people, including a five-year-old boy, were killed by gunfire during security force raids into villages of the northwestern province of Idlib, according to the Syrian Observatory for Human Rights.

A senior official of the opposition Syrian National Council said it wanted a minimum of three entry points for aid to enter Syria -- from Lebanon into Homs, from Jordan into Deraa and Turkey into Idlib.

Basma Kodmani, speaking to reporters in Geneva after talks with the ICRC, said Russia should put pressure on Assad to agree.

In Moscow, Russia said it was working on ensuring the secure transit of humanitarian aid but safe corridors themselves were not a good idea because they might lead to further violence.

It's logical to consider that if something goes wrong, the use of force would be permitted, Deputy Foreign Minister Gennady Gatilov told reporters in Moscow.

This would only aggravate the conflict.

In Washington, officials stressed the Obama administration was still seeking a negotiated solution but also hinted it could reconsider its stance on not arming Syria's opposition.

We don't want to take actions that would contribute to the further militarisation of Syria, because that could take the country down a dangerous path. But we don't rule out additional measures, White House spokesman Jay Carney said on Tuesday.

Analysts says Assad sees himself as in a fight for survival. Although some say the support around him is crumbling and the military is tiring, others say he could hang on for many months more before he joins Libya's Muammar Gaddafi, Egypt's Hosni Mubarak and Tunisia's Zine al-Abidine Ben Ali on the list of deposed Arab leaders, if he does at all.

There are also fears the revolt could flare into a religion-based civil war and spread across the volatile Middle East -- considerations that make arming the rebels a tricky proposition.

In a chilling example of the repression, activists also said troops and militia loyal to Assad summarily executed 27 young men on Tuesday in northern villages.

Several YouTube videos taken by local activists in the northern Idlib area, which could not be independently confirmed, showed the bodies with bullet wounds to the head or chest and hands tied lying dead in streets.

(Additional reporting by Erika Solomon and Mariam Karouny in Beirut, John Irish in Paris; Steve Gutterman in Moscow, Stephanie Nebehay in Geneva; Editing by Peter Millership; khaled.oweis@reuters.com; +962 6 4623776)