Police say four policemen in Nigeria's restive northeast were wounded after men attacked them with explosives at a security checkpoint.
Bauchi State police spokesman Mohammad Barau said Monday that two motorcycle-mounted men threw a parcel containing explosives at a police checkpoint in the city of Bauchi.
Barau did not say if the police suspected anyone. However, similar motorcycle-mounted attacks targeting security officers have been blamed on a radical Muslim sect locally known as Boko Haram in the city of Maiduguri, some 280 miles (450 kilometers) away.
The group has claimed responsibility _ in unverified statements _ for multiple May blasts that hit Bauchi, another city and a town near the capital, killing 18 people.
Boko Haram seeks the strict implementation of Shariah law in northern Nigeria.