British Foreign Secretary William Hague won't rule out military intervention in Syria, saying the situation there is beginning to resemble the violence which gripped Bosnia in the 1990s.

Campaigns of sectarian bloodletting gripped Bosnia for years during that decade, pulling the country apart and resulting in tens of thousands of deaths.

Hague told Sky News television that time was now "clearly running short" to implement international envoy Kofi Annan's ceasefire plan in Syria.

Asked if his government had ruled out the use of force, Hague said Sunday that the country was "on the edge of collapse or of a sectarian civil war so I don't think we can rule anything out."

The British minister's comments came as Syrian government forces pounded areas in the central province of Homs on Sunday, in a renewed push to regain control of rebel-held territories. Activists said at least 38 people had been killed in shelling there over the past 24 hours.

The assault focused on the town of Qusair, near the border with Lebanon, where activists reported at least six people died on Sunday alone. Three others died in shelling of the town of Talbiseh, north of Homs city, according to the Britain-based Syrian Observatory for Human Rights.

Also Sunday, Syrian forces unleashed a new round of heavy shelling and sent reinforcements to a mountainous area near the coastal city of Latakia where hundreds of rebels have set up base and which has also been the scene of fierce fighting in recent days.

Rami Abdul-Rahman, the director of the Observatory said at least 58 soldiers have been killed and more than 200 wounded in fighting there since Tuesday. His estimated death toll could not be independently verified.

Regime claims 'heinous' crimes committed

State-run news agency SANA said "terrorist groups" in Haffa attacked public and private institutions on Saturday and committed "heinous" crimes against civilians, setting fire to the national hospital and forcing people to leave their homes. It said troops killed a number of them and arrested several others, adding it was still pursuing gunmen and working to restore security to the area.

Six children were among 10 people killed by a shell that exploded in a house where they had taken cover during the fighting in the region on Saturday, the Observatory said.

Thousands have been killed since the Syrian uprising began in March last year and activists put the toll at more than 13,000. International envoy Kofi Annan brokered a cease-fire that went into effect on April 12 but has since been violated every day by both sides of the conflict.

Armed rebels have stepped up their attacks on government troops recently, taking their fight against President Bashar al-Assad to the capital Damascus, which on Friday saw some of the most intense fighting since the 15-month uprising began.

New opposition leader elected

Meanwhile, Syria's main opposition group in exile, the Syrian National Council, elected a Kurdish dissident as its new leader at a meeting in Turkey, a council statement said.

Abdulbaset Sieda, a 56-year-old activist who has been living for many years in exile in Sweden, was the only candidate to replace liberal opposition leader Burhan Ghalioun for the three-month presidency. He was elected unanimously during an SNC meeting Saturday night in Istanbul that stretched into early hours Sunday.

The Paris-based Ghalioun presided over the council since it was created last August but recently offered to step down over mounting criticism of his leadership and repeated renewals of his three-month term. Several prominent Syrian dissidents have quit the group calling it an "autocratic" organization no better than Assad's authoritarian rule.

They also complained the group was dominated by Islamists, including the fundamentalist Muslim Brotherhood.

The Syrian opposition has been hobbled by disorganization and infighting since the popular revolt against Assad began in March 2012. Its international backers have repeatedly appealed for the movement to pull together and work as one unit. The SNC itself has been plagued by infighting, hampering efforts by Western and Arab nations to help the opposition.