UNCONFIRMED reports suggesting that Russia was planning to expand its military support for Syrian President Bashar Assad prompted a warning from the U.S. that such actions could lead to a confrontation with coalition forces.

In Washington, the State Department issued a statement after U.S. Secretary of State John Kerry called Russian Foreign Minister Sergey Lavrov to express concern over unconfirmed reports “suggesting an imminent enhanced Russian military build-up” in Syria.

While not elaborating on or confirming the accuracy of those reports, the State Department said Kerry made clear to Lavrov that such actions “could further escalate the conflict, lead to greater loss of innocent life, increase refugee flows and risk confrontation” with the anti-Islamic State coalition operating led by the US that is carrying out strikes in Syria.

#Syria Nusra linked acc. posted pics of Russian made drone & jets flying over Western #Idlib. Huge if true. pic.twitter.com/1xPuUbD9an — Green lemon (@green_lemonnn) September 2, 2015

Supposedly the Tsezar Kunikov...added 2 September...caption: "Again to Syria" pic.twitter.com/5g8CIpr9w9 — RussianNavyBlog(ret) (@russiannavyblog) September 5, 2015

Russia has been a stalwart ally of Assad throughout Syria’s civil war and has provided diplomatic support and weaponry to help the Syrian leader maintain his grip on power. Moscow also maintains a small naval facility at the Syrian port of Tartous on the Mediterranean Sea.

The influx of troops - and possibly combat jets - comes as a key Syrian cleric was killed in a bombing yesterday.

Sheik Wahid Balous, was a prominent critic of Assad and had called on youth in Sweida province to refuse to serve in the military. He was also a critic of the Islamic State militants who have taken over a third of the country and are fuelling the civil war that has killed more than 250,000 people and wounded more than 1 million.

Balous, who was a strong supporter of rebels trying to topple Assad, died in one of two consecutive car bomb explosions, including one near the National Hospital in Sweida.

Unpopular regimen

Anti-government violence erupted at the weekend in a southern Syrian province that had largely stayed on the sidelines of the country’s civil war.

The violence in Sweida province, a stronghold of the Druze minority sect, followed the killing of a prominent cleric in explosions yesterday that claimed the lives of at least 25 others, activists and pro-government media said. Rioters holding the government responsible for the cleric’s death destroyed the statue of late Syrian President Hafez Al-Assad and besieged security offices, the Britain-based Syrian Observatory for Human Rights and other activist groups said.

The Observatory said the death toll rose Saturday to 37, including six security personnel killed in clashes with rioters.

Russian Warship Korolev Passed Through Istanbul With Cargo On Her Deck http://t.co/Ja2Wu7xTkB pic.twitter.com/SOoC7Xfcqa — Bosphorus Naval News (@Saturn5_) September 4, 2015

Russian Navy's N.Filchenkov heading back home after unloading the armored vehicles in Tartous https://t.co/VYpU0saan7 pic.twitter.com/Iv7MTfntCq — alper boler (@alperboler) August 31, 2015

The city had witnessed large rallies in the days before the explosions against the failure of the government to provide basic services. Activists reported that there was no internet service for the past few days.

Syria’s official news agency and other activist groups put the death toll from the blasts at 26. There was no immediate claim of responsibly for the bombings.

The Syrian government called the blasts “cowardly terrorist acts.” A police commander in the city, Mohammed Samra, said Sweida was “calm and stable” and denied any unrest, saying reports of anti-government violence were aimed at undermining security in the area.

Some of Balous’ supporters said in a statement they will expel security forces from Sweida province, which until now has largely stayed out of the fighting in Syria’s civil war.

Civil unrest

City elders appealed for calm, warning against attempts to drag the province toward violence. Another statement from the city’s Druze leaders urged supporters to be patient as the cleric’s brother, who was seriously wounded in the attack, recovers.

A 10th century offshoot of Shiite Islam, the Druze made up about 5 per cent of Syria’s pre-war population of 23 million people, and is split between supporters and opponents of Assad.

In neighbouring Lebanon, which also has a sizeable Druze population, the sect’s political leader Walid Jumblatt said Balous’s death was a “painful strike” to the community.

Learn about what the U.S. is doing to assist those affected by the crisis in #Syria and how you can help: https://t.co/jk3OkutLOA — Department of State (@StateDept) September 5, 2015

“It is time for the honourable citizens (of Sweida) to rise up in the face of the Syrian regimen that wants repression and to spread sedition,” he told the anti-government Syrian Orient TV.

The National Syrian Coalition opposition group in exile also blamed the Syrian government for the killing of the cleric, known as “the Dignity Sheikh,” saying it was part of an attempt to stop the anti-government protests in recent days. In a statement, coalition member Suheir Attasi said killing Balous only “increased the popular anger in the province.”