The dead toll from Monday's traffic accident in Egypt's central Sinai has risen to 21, a security source said, confirming that 25 others were injured.

A security vehicle carrying security personnel turned over on a bumpy road in Sinai on Monday, leaving 21 dead and 25 injured, the source told Xinhua.

The wounded, along with the bodies of the dead, have been taken to a hospital in Al-Arish, the capital of North Sinai, according to Tarek Khater, the Health Ministry's undersecretary, who was quoted by the official MENA news agency as saying that those in critical conditions will be transferred to Cairo.

Egyptian President Mohamed Morsi has ordered the armed forces and the Interior Ministry officials to head to the accident site to help rescue the injured, and expressed his condolence to the victims' families.