A Sinai-based armed group Ansar Bayt al-Maqdis has claimed responsibility for an attack last week that targeted the Egyptian Interior Minister, and promised more attacks in revenge for a crackdown on Egypt's Islamists.
"God allowed us to break the security system of the minister of interior ... through a suicide operation committed by one of Egypt's lions that made the interior butcher see death with his eyes, and what is to come will be worse," the group said on Sunday in a statement posted on a website.
Thursday's daylight attack occured as a suicide car bomber blew himself up next to Interior Minister Mohamed Ibrahim's convoy as he left his home in Cairo in an armoured limousine.
The bomber, a passer-by and an unidentified person were killed and more than 20 wounded.
Last year the same group, whose name means "Supporters of Jerusalem", claimed responsibility for rocket attacks launched on Israel from Sinai.
Sinai's eastern border with Israel and Gaza is a particularly sensitive one, and Israel made its concerns known when armed groups expanded into a security vacuum left by the fall of Egypt's former President Hosni Mubarak in 2011.
Critics of Egypt’s deposed President Mohammed Morsi have accused him of helping the armed groups by releasing fighters with links to Sinai shortly after he took office in June 2012.
Morsi argued that all those set free had either completed their terms or failed to receive due process because they had been tried by special military courts.
Attacks on Egyptian security forces in Sinai have become a near-daily occurrence, and about 50 have been killed since Morsi was deposed two months ago.
On Saturday, the Egyptian military helicopters conducted several air strikes in the region, targeting anti-state fighters.