Syrian rebels said they captured a major base from the army in the south of the country yesterday, a setback that would increase pressure on President Bashar al-Assad after his recent losses elsewhere.
Syrian officials could not immediately be reached for comment. State TV had earlier said the army had repelled an attack in the area near the Jordanian border targeted by the rebels early yesterday.
"We announce the liberation of Liwa 52," said Issam al-Rayyes, spokesman for the 'Southern Front' alliance of mainstream rebel groups. Liwa 52, or the 52nd Brigade, is one of the biggest Syrian army bases in the area.
The southern region near the border with Jordan and Israel is one of the areas where insurgents have inflicted significant defeats on Mr Assad in the last three months, notably the capture of the Nasib border crossing with Jordan on April 1.
Less than 100km south of Damascus, the area is one of the last major footholds of mainstream rebels who have been eclipsed elsewhere in Syria by jihadist groups such as Islamic State and the Nusra Front, al Qaeda's Syrian arm.
Nusra and other hardline Islamist groups also have a presence in the south, including Ahrar al-Sham, which said it was involved in the attack.
The rebels have failed in previous attempts to capture the base.
The report earlier on Syrian state TV said the army had repelled an attempt by "a terrorist group" to infiltrate a military position. It said a number of the attackers had been killed and wounded, including a rebel commander. The air force was carrying out raids in the area, it added.
'The Southern Front' alliance has been coordinating operations against Mr Assad from a joint command centre in Jordan.
They have received some support from foreign states that want to see Mr Assad gone, including Gulf Arab governments.
"It is very important because it is the second biggest base the regime has (in the south)," said Saber Safar, a former army colonel whose 'First Army' rebel group was one of a number of factions that said they took part.
The rebels had fired more than 100 missiles at the base during the attack, the opposition-affiliated Orient News TV station said.
Since late March, an alliance of insurgents including the Nusra Front have seized nearly all of the northwestern province of Idlib at the Turkish border. Islamic State has also seized the city of Palmyra from government control.
The setbacks for Mr Assad have prompted Western policymakers to suggest a window of opportunity for a political deal may be opening in Syria.
But the defeats have also triggered renewed statements of support for Mr Assad from Iran, whose backing has been crucial to his survival.
Thousands of foreign fighters have travelled to Iraq and Syria in the year since Islamic State of Iraq and the Levant's (Isil) lightning sweep through the two territories.
According to the most recent publicly available estimates, released by King's College London's International Centre for the Study of Radicalisation in January, Tunisia has contributed the largest contingent, with some estimates putting the figure as high as 3,000.
The foreign loyalists can expect to join fighting battalions, or even take up positions in the extremist group's extensive bureaucracy, which implements Islamic law and harvests taxes across its territory.
Saudi Arabia - a country battling Isil terrorism against Shia residents in its eastern province - is thought to be the second most prolific source of foreign fighters, with up to 2,500 people believed to have joined the fray in Iraq and Syria.
Nearly a fifth of fighters are residents or nationals of Western European countries, and an estimated 1,200 people have travelled from France alone.
These figures will have risen in recent months as Isil has attracted more fighters to help it consolidate control over three provincial capitals - Raqqa, Mosul and Ramadi.
This flow of foreign fighters has alarmed governments around the world, raising fears that returnees may plot attacks in their home nations.
Scotland Yard said that at least half of the 700 British residents - a statistic from the British police - suspected of fighting alongside Isil are now back in the UK.
When pressed last month on how the security services will treat the case of three schoolgirls who have reportedly escaped from Isil, after initially seeking to join the jihadist group in Syria, Home Secretary Theresa May said that decisions are made on a "case-by-case basis". (© Daily Telegraph, London, and agencies)