The Guardian reports: At least 90 people, including many children, have been killed after Syrian forces shelled and attacked the town of Houla in Homs province, according to anti-government activists.

The death toll reported on Friday was one of the highest in one area of the country since an internationally brokered ceasefire came into effect last month.

The UK-based Syrian Observatory for Human Rights said the violence began when security forces opened fire on an opposition protest in Houla. Anti-government forces retaliated and the army began shelling the area, killing an estimated 90 people.

A spokesman for the United Nations’ envoy to Syria told the Associated Press in an email on Saturday that international monitors were travelling to Houla “as we speak” to investigate.

The surge in violence came as Ban Ki-moon, the UN secretary general told the UN security council there had been some progress in reducing violence, but the overall situation remained very serious.