BEIRUT -- A Syrian search-and-rescue group says the death toll from an explosion that destroyed two apartment buildings in a rebel-held town in the country's northwest the previous day has risen to 67. The Civil Defense, also known as the White Helmets, says rescuers were still searching through the rubble in Sarmada on Monday, looking for survivors from the blast. It says 35 wounded people have already been found.

The Britain-based Syrian Observatory for Human Rights gave a slightly higher death toll, saying 69 died, including 17 children. The Observatory says 52 of the victims were civilians; the rest were militants or couldn't be identified.

The Observatory said an arms depot in the basement of a building had detonated, bringing down two five-story apartment buildings. The report could not be independently confirmed, but the Observatory has a history of reliable reporting from the Syrian war, relying on a network of activists, medics and other sources on the ground.