New amateur video purports to show the shelling of Houla on Friday that left at least 108 people dead, including many women and children.
People are seen fleeing as explosions and gunfire are heard in the background.
The pictures uploaded onto a social media website cannot be verified.
The UN human rights office has said that only a few people died from artillery and tank fire. Survivors have told UN investigators that most were summarily executed by militia loyal to the Syrian regime, who came from a nearby village.
Tuesday saw more deaths around the country – at least 19, including 12 civilians, according to the foreign-based Syrian Human Rights Observatory.
It said government forces were becoming exhausted after suffering many losses at the hands of rebels in recent days.
At a makeshift hospital in Al-Qusayr, northwest of Homs, doctors struggled to deal with wounded rebels soldiers and civilians.
The town has been besieged for six months and one of the main supply routes from Lebanon has been cut off.
The main town hospital was taken over by the Syrian army, which is then said to have installed snipers’ nests in the building.