Suspected militant Islamists have ambushed a convoy of about 200 vehicles on a major highway in north-eastern Nigeria, killing a police officer and a truck driver, the local Vanguard newspaper has quoted witnesses and police as saying. The convoy included the burial party of a policewoman who died last week, as well as a busload of mobile police unit officers. It came under fire yesterday from suspected Boko Haram gunmen on the highway between the capital of Borno state, Maiduguri, and the town of Damboa, the newspaper reported. It quoted witnesses as saying that anti-aircraft guns and other heavy weapons were used in the estimated 30-minute long attack on the convoy, which was being escorted by police and government troops. Vehicles on the Maiduguri-Damboa highway usually travel in a convoy under security escort because of the threat posed by militant Islamists.