Forty-nine school children have been killed and 18 injured when a train ploughed into their bus in southern Egypt.
Transport Minister Rashad al-Mateeni and the chief of the state-run rail authority, Mustafa Qenawi, resigned following Saturday's accident, state television reported.
There were about 60 pupils on the bus when it was hit by the train at a level crossing at Manfalut in the province of Assiut, about 350 kilometres south of Cairo. The children were aged between four and six.
"The deaths have now reached 49. There are 18 children injured," Governor Yehya Keshk told state television.
"There is a team of 45 doctors looking after the injured children."
A state television correspondent described the scene as "terrifying" with the blood-splattered bodies of children on the ground, before they were taken to nearby Manfalut hospital.
A source at the Transport Ministry was quoted by state television as saying the bus driver and two helpers were killed.
President Mohamed Morsi has ordered the Prime Minister, the Defence and Health ministers and the Assiut Governor "to offer all assistance to the families of the victims," MENA said.
"President Mohammed Morsi ordered a swift probe into the accident and those responsible for it to be brought to justice," a statement from the President's office said.
Keshk has ordered the "formation of a fact-finding committee" to investigate the accident, but in similar tragedies in the past, such panels have done little to shed light on the details and less still to bring about accountability.
Road accidents are common in Egypt and largely blamed on reckless driving and bad roads.
Ordinary Egyptians have long complained that the government has failed to deal with the country's chronic transport problems, with roads as poorly maintained as train lines.
Earlier this month, five people were killed and dozens injured when two trains collided in Fayyum province, south-west of Cairo.
A month earlier, 28 police died in the Sinai peninsula when the driver of their bus lost control of the wheel.
Egypt's deadliest train accident took place in the village of Al-Ayyat in February 2002 when a train travelling from Cairo to Luxor caught fire after a cooking gas cylinder exploded on one of its carriages.
Trains are often overcrowded in Egypt, particularly in lower-paying carriages, adding to the safety hazard.