An attack on a bus early on Monday morning in northern Syria has killed 13 people, most of them government troops, the country’s defence ministry said. A ministry statement said that 11 government troops and two civilians were killed in what it said was a terrorist attack on a civilian transit bus. It said another three soldiers were wounded. Syrian state news agency SANA said the attack took place in the Jabal al-Bishri region of the vast province of Raqqa. The Syrian Observatory for Human Rights said the ambush had been carried out by Islamic State sleeper cells that launch hit-and-run attac…