Egyptians gather at the site of a massive bomb attack on one of the main police stations in al-Arish, Sinai, Egypt, April 12, 2015. [Photo/IC]

Sunday's explosions came one day after an Egyptian court delivered death sentences to the chief leader of the outlawed Muslim Brotherhood (MB) group Mohamed Badie and 13 other MB members and life imprisonment terms to 37 MB members over violence charges.

The MB spiritual leader and the other defendants are charged with running an operational room to mobilize group members to target security forces and spread disorder after the dispersal of two major sit-ins in Cairo August 2013.

Sinai-based Ansar Bayt al-Maqdis, which has recently pledged allegiance to the Islamic State (IS) militant group, claimed responsibility for most of the anti-government attacks in Egypt.

Military operations escalated notably in restive Sinai Peninsula after the ouster of Islamist President Mohamed Morsi by the army in response to mass protests against his one-year rule in 2013.

The militants claimed that the attacks, mainly against the army and the policemen, were in retaliation for the security dispersal of two pro-Morsi sit-ins which left nearly 1,000 killed.

Earlier in April, at least 15 military men and four civilians were killed and about 40 others injured in a series of armed attacks on several checkpoints in Sheikh Zuweid city, while security raids on the same day killed around 55 militants.