As many as 40 children aged four to six years old have been killed in a crash involving a school bus and a train in the central Egyptian province of Assyut, officials say.

The bus was carrying about 60 children from a nursery school when it was hit by a train near Manfalut, 350km (230 miles) south of Cairo.

The Egyptian transport minister has resigned, state media said.

Egypt's roads and railways have a poor safety record.

Egyptian President Mohammed Mursi ordered his ministers to offer support to the families of those killed, BBC News reported.