No let-up in Aleppo

Sources in Aleppo said the bomb of a type decried for its crude impact set aflame a fuel shop in a rebel-held eastern neighborhood on Thursday, a day after Syrian President Bashar al-Assad denied that his forces used such explosives.

An Aleppo-based activist Abu Raed told the news agency Associated Press that many among the 20 people killed were bystanders who died in the flames. The Britain-based Syrian Observatory for Human Rights put the toll at 18 killed.

Battle around headquarters site

Across Aleppo, on its western flank, security sources said battles continued Thursday around the intelligence headquarters where a rebel attack began Wednesday with a huge blast.

It resembled a tactic often used by rebels of digging tunnels and setting off explosives.

A Syrian military sources quoted by the news agency AFP said the army's counter-attack had on Thursday killed and wound "many" rebel gunmen.

UN plan at a 'dead end'

Wednesday's rebel attack, which reported claimed the lives of 20 government personnel and 14 rebels, followed opposition rejection on Sunday of a peace plan for Aleppo proposed by UN envoy Staffan de Mistura.

He had held talks in Damascus on Saturday, but on Thursday a member of Syria's Opposition Coalition, Samir Nashar, said the plan was at a "dead end."

"De Mistura's initiative does not address even the minimum of rebel demands," Nashar said.

The observatory said seven civilians had also been killed in a regime air strike near a school in Syria's northern province of Idlib.

Fight IS on the ground, says Saudi Arabia

Visiting Riyadh, US Secretary of State John Kerry was told by host Saudi Arabia's Foreign Minister Prince Saud al-Faisal that the US-led coalition staging air strikes against the "Islamic State" group also needed to fight the jihadists on the ground.

Since last April the self-styled "Islamic State" (IS), also known by its Arabic acronym Daesh, has seized swathes of northern and eastern Syria and into Iraq.

Faisal said Saudi Arabia "stresses the need to provide the military means needed to face this challenge on the ground."

So far, US President Barack Obama has backed the air campaign involving several Arab countries but ruled out US ground combat against IS in Syria.

The coalition's joint Task Force in a statement on Thursday said US and coalition forces had since Wednesday targeted IS in 12 air strikes in Syria and Iraq, including the Syrian city of Tal Hamis and IS units near the Iraqi city of Falluja.

New tack by Syrian opposition

Visiting Paris, the exiled head of the main opposition Syrian National Coalition, Khaled Khoja, said Assad's ouster no longer remained an opposition pre-condition to enter into a new round of talks with the regime.

His remarks in an interview with the AFP news agency came less than a week since the exiled coalition met in Paris with Syria's domestic National Coordination Committee for Democratic Change (NCCDC).

"We insist on the goal of toppling Assad and the security services… It is not necessary to have these conditions at the beginning of the process, but it is … necessary to end the process with a new regime and a new free Syria," Khoja said.

After talks with Khoja, French President Francois Hollande said Assad was "the main cause of his people's suffering, and for the rise of terrorist groups in Syria."

Since March 2011, Syria's conflict has clamed more than 220,000 lives and forced half of the population to flee their homes, many into neighboring countries.

ipj/sms (AFP, AP, Reuters)