A powerful blast hit the Italian consulate in the Egyptian capital on Saturday, partly destroying the facade of the building in central Cairo, an AFP correspondent at the scene reported.

It was not immediately clear what caused the blast, which occurred at about 6:30 am (0430 GMT), when the consulate would have been closed.

Medics at the site of the explosion told AFP that it wounded two policemen stationed outside the consulate, as well as three passers-by.

Hundreds of soldiers and policemen have been killed in militant attacks in Egypt since the army deposed Islamist president Mohamed Morsi in July 2013.

Over the same period, at least 1,400 people, mostly Islamists, have killed in a security crackdown on protests.

The deadliest attacks against the security forces have occurred in the Sinai Peninsula, most of them claimed by the Islamic State jihadist group.

But Cairo and cities and towns in the Nile Delta have also been targeted in such attacks, which have left hundreds of soldiers and police dead. (AFP)