Up to 47 people, mostly school children, were killed when a train crashed into their bus which had crossed the tracks at an unmanned railway gate in a city south of Cairo on Saturday, the official state news agency and a doctor said.

A senior security official in Assiut, near the crash site, said 44 of the dead were children, aged around four to eight. Two women and a man, who was probably the bus driver, also died, he added.

The state news agency said another 13 people were injured. A medical source said as many as 28 were injured, 27 of them children.

Egypt's roads and railways have a poor safety record and Egyptians have long complained successive governments have failed to enforce basic safety standards, leading to a string of deadly accidents.

"They told us the barriers were open when the bus crossed the tracks and the train collided with it," said Mohamed Samir, a doctor at Assiut hospital where the injured were taken, citing witness accounts.

He said the bodies of many of those killed were severely mutilated, indicating the force of the crash, which took place in the city of Manfalut, near Assiut, about 300 km south of the capital.

"I saw the train collide with the bus and push it about 1 km along the track," said Ahmed Youssef, a driver. Another witness also said the train hit the bus with great force, smashing up the bodies.

Transport Minister Mohamed Rashad offered his resignation, which President Mohamed Mursi was considering, state media reported.

Mursi ordered his ministers to offer support to the families of those killed, the official news agency said. Prime Minister Hisham Kandil ordered those responsible for the crash be investigated.

Families of those involved in the crash protested at the scene, the state news agency reported. Officials sought to reassure them that the case would be investigated and they would receive help, it said.

Earlier this month, at least three Egyptians were killed and more than 30 injured in a train crash in Fayoum, another city south of Cairo. In July, 15 people were injured in Giza, close to the capital, when a train derailed.

Egypt's worst train disaster was in 2002 when a fire ripped through seven carriages of an overcrowded passenger train, killing at least 360 people.

Many more have been killed in rail accidents since then despite pledges from successive government to improve safety. Accidents involving multiple deaths are also common on Egypt's poor road network.-Reuters