The death toll from regime airstrikes on Syria's Aleppo has risen to 85, a monitoring group said Sunday, as the conflict grinds on after 10 days of inconclusive peace talks.

The latest fighting came as a suicide car bomb in a Hezbollah stronghold across the border in Lebanon killed four people Saturday, stoking fears of further regional spillover of the conflict.

Helicopters hit rebel-held areas of Aleppo on Saturday with barrels packed with explosives, a controversial tactic widely condemned by rights groups as indiscriminate.

"At least 85 people were killed, including 65 civilians, 10 of whom were children," the Syrian Observatory for Human Rights said.

Attacks targeted several areas of the city, with 34 of the dead in the Tareq al-Bab area alone.

Aleppo has been divided between regime and rebel-held areas since opposition fighters launched a massive offensive in the city in mid-2012.

Fierce fighting between the two sides has left swathes of the historic city in ruins.

The Observatory said 10 of those killed on Saturday were jihadists from the Syrian Al-Qaeda affiliate, Al-Nusra Front, who were in their headquarters when it was hit. Another 10 bodies could not be identified.

In December, government warplanes launched a sustained blitz on the city that killed hundreds of people, the Observatory said, most of them civilians.

Regime forces recently launched an offensive on rebel-held areas in the east of the city, with Syrian Defence Minister General Fahd al-Freij visiting parts of northern Aleppo province on Friday.

State news agency SANA cited Freij as saying he was offering thanks for the army's "great victories and their liberation of many areas in Aleppo."

The latest aerial assault came the day after Syrian government and opposition delegations wrapped up peace talks in Geneva.

The 10 days of talks yielded no tangible results and the government team said it was unsure whether it would return to the negotiating table.

Conflict spills into Lebanon

The Observatory said Saturday the overall death toll from Syria's civil war had topped 136,000, with January one of the bloodiest months since the conflict erupted in March 2011.

The war started after security forces cracked down on peaceful anti-government demonstrations, sparking an armed uprising against President Bashar al-Assad.

The Britain-based monitor said the toll at the end of January was at least 136,227.

Among the dead were 47,998 civilians, including more than 7,300 children.

The Observatory said the real toll could be much higher because of the secrecy of rebels, jihadists and the regime about casualty figures.

The conflict has displaced millions of people and spilled over into neighbouring Lebanon and Iraq, which share Syria's sectarian tensions.

Saturday's bombing in Lebanon killed at least four people and wounded 15 at a petrol station in the eastern town of Hermel, a stronghold of the Shiite Muslim movement Hezbollah near the border.

Sectarian tensions have soared in Lebanon since Hezbollah announced that it was dispatching fighters to aid Assad's troops.

Much of Lebanon's Sunni population supports Syria's Sunni-led rebels, and Lebanese jihadists have claimed a series of attacks targeting the Shiite movement.

Al-Nusra Front in Lebanon, a group named after the Syrian Al-Qaeda affiliate but whose links to its namesake are unclear, claimed Saturday's attack on Twitter, saying it was a response to Hezbollah involvement in Syria.

The attack is the seventh targeting Hezbollah strongholds since the group said it had sent fighters to Syria.

The United Nations urged Lebanon's feuding factions to refrain from getting involved in Syria's crisis following the car bomb.

The United Nations Security Council issued a statement condemning the "terrorist attack" and called for the perpetrators to be brought to justice.