At least 11 people have died in north-west Syria after a police van carrying prisoners was blown up on the Idlib-Ariha highway, reports say.
Sana, the official Syrian news agency, said the police van was attacked by an “armed group” on the Idlib-Ariha highway. An opposition group confirmed the incident but did not say who carried it out.
The news came as the Arab League hears a report by monitors observing implementation of its peace plan.
The league is due to decide whether to extend its mission in the coming days.
The 165-strong mission expired on Thursday with no sign of a halt to the government’s crackdown on protesters.
Analysts say the league is expected to renew the mission for another month.
The reports said Saturday’s attack happened in the Mastoumeh area in Idlib province.
Sana initially said 14 people had died, and 26 prisoners and six police were injured.
An ambulance which came to the aid of victims was also attacked, the agency added.
The opposition Syrian Observatory for Human Rights put the number of dead at 11. It said the van had been hit by several roadside bombs.
No-one has claimed responsibility for the attacks.
Violence across Syria on Friday resulted in seven people being killed by security forces, opposition groups said.
The UN Security Council was told earlier this month that 400 people had been killed during the monitors’ first 10 days in Syria.
The UN had previously said that more than 5,000 had died since protests against President Bashar al-Assad erupted last March.
The government in Damascus says that some 2,000 members of the security forces have also been killed combating “armed gangs and terrorists”.
In a separate development, the US says it is considering closing its embassy in Damascus because of increasing safety concerns.
Officials in Washington say they are talking to the Syrian authorities, as well as to the British and Chinese governments, who have embassies nearby. But no final decision had been taken.
The conclusions reached by the Arab League mission’s head, Sudanese Gen Mohammed al-Dabi, had been due to be discussed by a committee of ministers on Saturday, but unconfirmed reports say ministerial talks will not now be held earlier than Sunday.
The panel is chaired by Qatari Prime Minister Sheikh Hamad al-Thani, whose country has previously suggested sending Arab peacekeepers to Syria.
Damascus has firmly rejected the idea.
It appears that there is no clearly thought out alternative to the monitoring mission, and no appetite – as yet – for a radical change of course.
League officials have already hinted that the most likely outcome will be to renew the mission for another month, possibly doubling the number of observers on the ground.
Last week, the head of the Arab League’s Cairo operations room, Adnan al-Khudeir, said the observers would remain in 17 difference places around Syria until the final decision is made.
Although the mandate of the observer mission came to an end formally on Thursday, the agreement covering it provides for an extension for a second month if both sides agree.
So far there has been no suggestion from Damascus that the monitors should be withdrawn.