BEIRUT • Syrian rebel factions will issue a statement welcoming the US-Russian deal for a ceasefire and aid deliveries in Syria, but with reservations about the handling of violations by the government side, a rebel official said yesterday.

But even as the rebels and world powers threw their weight behind the agreement, a barrage of unidentified raids left scores dead in opposition territory in two key northern cities on Saturday. At least 62 people - including 13 children - were killed in heavy bombardment on Idlib city, the Syrian Observatory for Human Rights said yesterday.

A further 12 civilians were killed in unidentified strikes on several neighbourhoods of Aleppo city, and 18 people died in bombardment of other parts of Aleppo province, the Observatory said.

"The factions welcome a ceasefire and welcome the incoming of aid, but have reservations about some points... what are the sanctions if the regime doesn't abide by it?" said Zakaria Malahifji of the Aleppo-based rebel group Fastaqim.

Rebel groups believe they are treated unfairly by the deal and complain that they were not consulted about it, he said. "A big part of the agreement serves the regime and doesn't apply pressure on it and doesn't serve the Syrian people," Malahifji added.

The ceasefire will not apply to the Islamic State in Iraq and Syria (ISIS) or Jabhat Fateh al-Sham, previously known as the Al-Nusra Front until it broke formal allegiance to Al-Qaeda and changed its name.

The United States on Saturday warned insurgents they would face "dire consequences" if they cooperate with Jabhet Fatah al-Sham, which fought alongside a range of mainstream and Islamist rebel groups during intense battles in recent weeks in southern Aleppo.

Iran welcomed the proposed ceasefire, but said a monitoring system was needed to stop it being exploited by "terrorists".

"Iran welcomes any establishment of a ceasefire in Syria and facilitating of access of all people of this country to humanitarian aid," said Foreign Ministry spokesman Bahram Ghasemi.

"Given the experience of a few months ago, the ceasefire must be sustainable... and must not be exploited as an opportunity for terrorist groups to revive their power and transfer fighters and weapons," he added, referring to a truce that collapsed earlier this year.

"The continuation and sustainability of a ceasefire relies on the creation of a comprehensive monitoring mechanism, in particular control of borders in order to stop the dispatch of fresh terrorists, as well as weapons and financial resources for the terrorists," said Mr Ghasemi.

Hizbollah has also announced its support for the truce deal for Syria, where the Lebanese Shi'ite movement has intervened militarily on behalf of President Bashar al-Assad.

In a statement published late on Saturday on its official media arm Al-Manar, the group's unnamed "field commander for Syria operations" said Hizbollah "stands with the ceasefire". But it pledged to pursue an "open, relentless war against the terrorists" of the ISIS group and Al-Nusra Front.

REUTERS, AGENCE FRANCE-PRESSE