Syria 'in contravention' of peace plan, says UN chief
The Syrian government is "in contravention" of an internationally agreed peace plan, UN Secretary General Ban Ki-moon has warned.
Mr Ban "remains deeply troubled" by the continued presence of heavy weapons and troops in Syria's cities as reported by UN monitors, his spokesman said.
Mr Ban demanded that Damascus comply with the peace plan without delay.
The comments come as up to 70 people were killed in an attack on a house in Hama, according to Syrian activists.
They said several houses in the Masha at-Tayyar district in southern Hama were destroyed by a big explosion.
State media said 16 people died in the blast in a house used as a bomb factory by "armed terrorist groups".
The violence comes despite a UN-brokered ceasefire - part of the six-point peace plan proposed by the joint UN-Arab League envoy Kofi Annan.
The plan calls on Damascus to withdraw troops and heavy weapons from cities.
In a separate development, the Arab League said it would urge the UN Security Council to act "immediately" to protect Syrian civilians.
In a statement, the league said the issue would be raised at next week's council meeting.
France earlier said the council should consider the use of force in Syria if the peace plan fails to stop the violence.
Following the blast in Hama, activists posted video on the internet showing a scene of devastation, with bodies being pulled from the rubble.
One report said 13 children and 15 women were among the dead.
They said the blast was caused by government shelling or even a Scud missile attack.
The opposition Syrian National Council has called for an emergency UN Security Council meeting "so that it can issue a resolution to protect civilians".
It says nearly 100 people have been killed in Hama in recent days.
The level of devastation seen would have been difficult to achieve by conventional shelling, the BBC's Jim Muir in Beirut says.
State television showed pictures of injured children in hospital and says that a group using the house to make bombs detonated them accidentally.
The reports cannot be independently verified owing to government restrictions on foreign media.
Meanwhile, a video has emerged which purportedly shows a man being buried alive by security forces, allegedly for sending material to TV stations.
Its authenticity could not be confirmed.
The unnamed man, who is said to be a media activist, is seen pleading for his life as earth is shovelled over his head. He then goes silent.
What appear to be members of the security forces are then heard cursing him for receiving money for sending material to Arabic satellite TV stations.
The video was said to have been leaked by sympathisers.
The UN says about 9,000 people have died since pro-democracy protests began in March 2011. In February, the Syrian government put the death toll at 3,838 - 2,493 civilians and 1,345 security forces personnel.