International News

By Erika Solomon

BEIRUT (Reuters) - Rebels fighting for control of the Syrian town of Qusair called for reinforcements on Wednesday to repel forces loyal to President Bashar al-Assad in a civil war which is spreading violence through an already volatile region.

Opposition fighters said air strikes and shelling rocked the small town on the Syrian-Lebanese border that has seen some of the fiercest fighting in months in the two-year-old war that has so far cost at least 80,000 lives.

The fighting has drawn in fighters from Lebanon's Hezbollah movement, the latest sign of outside involvement in the war and evidence, according to Britain, that Iran and its allies in the militant group are lending increasing support to Assad.

After months of warnings from regional and international experts, violence is now spilling over Syria's borders, with clashes between pro- and anti-Assad factions in the Lebanese city of Tripoli and exchanges of fire between Syrian and Israeli forces in the Golan Heights.

Alarmed by the prospect of a wider conflict, the United States and Russia have agreed to back international peace talks intended to bring the rebels and Syrian government back to the table, although expectations of a breakthrough are low.

Security fears following bombings that killed 51 people in the Turkish town of Reyhanli earlier this month prompted Turkey on Wednesday to close a nearby border crossing with Syria. Turkey has accused Syria of involvement in the attacks. Damascus has denied any role.

While rebels are reinforced by foreign Islamists loyal to al Qaeda, the high-profile involvement of Iranian-backed Hezbollah on the government side has been accompanied by a report from a senior U.S. official of the presence of Iranians in Qusair.

SENATE BOOST

In a boost to the rebels, a U.S. Senate panel voted overwhelmingly on Tuesday to send them weapons, but it was not clear who would get the arms even if the bill succeeds.

The Senate Foreign Relations Committee voted 15-3 for legislation that would send arms to "vetted" moderate members of the Syrian opposition, the first time U.S. lawmakers have approved such military action in Syria.

The measure will now be considered by the full Senate, where a vocal group of legislators has been pushing for President Barack Obama to do more to help the rebels.

There is less enthusiasm for arming the rebels in the Republican-controlled House of Representatives, so it is not clear whether a Senate bill would ever get through Congress and reach Obama and be signed into law.

The outcome in Qusair will determine the status of important rebel supply routes into Syria and whether Assad can ensure access to important northern areas. It could also mean devastation for areas of nearby Lebanon.

Sunni rebel leaders have warned of sectarian revenge attacks against Shi'ites and Alawites on either side of the Syrian-Lebanese border if rebels lose Qusair. Fighters speak of a tacit agreement among their units to launch village by village attacks should they lose the town of 30,000.

George Sabra, acting head of the opposition National Coalition, called on fighters to send arms and men to the Qusair area, citing concern over sectarian violence and "foreign invaders" from Hezbollah and Iran.

WEAPONS APPEAL

"Everyone who has weapons or ammunition should send them to Qusair and Homs to strengthen its resistance. Every bullet sent to Qusair and Homs will block the invasion that is trying to drag Syria back to the era of fear," Sabra said in a statement.

Assad's forces are intent on seizing Qusair in order to cement their hold on a belt of territory that connects the capital Damascus to Assad's stronghold on the Mediterranean coast, home to his minority Alawite sect, an offshoot of Shi'ite Islam that has largely supported him.

Seizing Qusair would also allow Assad to sever links between rebel-held areas in the north and south of Syria.

With Shi'ite Hezbollah prominent in the fight in Qusair, its involvement could drag Syria's civil war - which already pits mainly Sunni Muslim rebels, including radical Islamists and foreign fighters, against an Alawite-led army - into a more regional sectarian conflict.

Sabra warned that Hezbollah forces in Qusair could enflame Sunni-Shi'ite tensions across the Middle East.

"The invasion will light a sectarian fire that will destroy relationships between countries in the region and their people. No one will benefit other than Israel."

Pro-Assad media have reported major advances for Hezbollah and state forces. Rebels deny they have lost ground.

Some opposition sources privately said they believed that the army, lead by Hezbollah ground units, has seized about 60 percent of the town. But they say rebels are fighting back hard, as they consider it a battle that could determine the fate of the uprising.

EXPLOSIONS

"If we lose Qusair, we lose Homs, and if we lose Homs, we lose the heart of the country," said Ahmed, a rebel speaking by Skype from the nearby town of Homs as explosions and gunfire crackled in the background.

One rebel source, who asked not to be named, said Assad and Hezbollah forces had cut most of the opposition's overland supply lines into Qusair. But he said the rebels were still able to bring some supplies and fighters in through secret tunnels.

An analyst close to Qatari officials said the Sunni Gulf state, which has funneled money and weapons to the opposition, was looking for new routes to send in supplies to Qusair.

Rebel forces from other parts of Syria appear to have taken the call for support seriously.

The large Islamist Tawheed Brigade in the northern province of Aleppo published a video of a 30-car convoy it said was heading to Qusair.

Sedans and pickup trucks loaded with artillery and fighters sped down the highway, with rebels waving black Islamist banners shouting "God is Great."

As countries in the anti-Assad "Friends of Syria" alliance gathered for talks in Jordan, British Foreign Secretary William Hague said Iran and Hezbollah were "propping up" Assad.

"It is very clear that the Syrian regime is receiving a great deal of support, increasing support in recent months from outside Syria from Hezbollah and Iran. This is a regime that is increasingly dependent on external support," Hague said at a news conference in Amman.

Hague said Britain would urge international powers to set a date in the next few days for an international conference to try to end the Syrian conflict.

The talks are expected to be held in Geneva next month.

(Writing by Giles Elgood; editing by Philippa Fletcher)