A bomb has struck a bus carrying Egyptian policemen in the Nile Delta region, killing three and wounding 33, officials have said.

Monday’s attack occurred in the province of Baheira, 260km north of the capital Cairo, while the policemen were travelling on a civilian bus to work.

"Three policemen were killed, including one who succumbed to his wounds in hospital," health ministry spokesman Hossam Abdel Ghaffar told the AFP news agency.

He said one of the injured remained in critical condition. No group has claimed repsonsibility for the attack.

Armed groups have killed scores of policemen and soldiers in violence following the 2013 overthrow of Mohamed Morsi, the country's first democratically elected president who took office following the overthrow of longtime ruler Hosni Mubarak.

Egypt's affiliate of the Islamic State of Iraq and the Levant (ISIL) group regularly claims responsibility for attacks against security forces.

While mostly centred on the Sinai Peninsula, ISIL has in recent months carried out more attacks Cairo, including against foreign targets.

On Thursday, a car bomb claimed by ISIL tore through a police building in the capital injuring at least 27 people.

The group also claimed a car bomb attack targeting the Italian consulate in central Cairo on July 11 which killed a passerby.

The consulate bombing was followed by the abduction of Croatian engineer Tomislav Salopek, who ISIL later claimed to have beheaded.

Source: Agencies