Jihadis and other rebel groups made advances against the Syrian army north of Hama on Thursday, a monitor said, part of their biggest offensive for months, underscoring bleak prospects for peace talks that resume later in the day.

A Syrian military source said the government was summoning reinforcements for a counter-offensive. ¡°We have absorbed the attack and we are consolidating defence lines set up in the areas breached,¡± he told Reuters.

Since their Hama assault began late on Tuesday, rebels have captured at least 11 villages and towns from the army, the Syrian Observatory for Human Rights, a Britain-based war monitoring group, said.