At least 235 have been killed in the deadliest insurgent attack to strike Egypt of modern times, where attackers bombed a Sinai mosque and gunned down fleeing worshipers and ambulance services. Witnesses say a bomb struck a mosque in the town of Bir al-Abed, in the north Sinai region. Scores of gunmen set up outside the building in off-road vehicles, then opened fire on those trying to escape. More than 100 are also reported wounded. There's been no immediate claim of responsibility but Egypt's battle against insurgents in Sinai has worsened since the 2013 revolution, and now includes members of Islamic State. President Abdel Fattah al-Sisi has declared three days of mourning in the country, vowing vengeance on the perpetrators.