An explosion in the Egyptian city of Rafah near Gaza Strip destroyed part of an intelligence building, Al Arabiya correspondent reported early on Sunday.
Large numbers of security forces were deployed at the scene of the explosion and sealed off the area while search for possible explosives was underway.
The cause of the blast was not immediately known, but Egypt has been fighting Islamist militants in Sinai for several months. The collapse of the former regime and the deterioration of security conditions in Egypt created a security vacuum in the desert peninsula.
The security lax was exploited by armed militants seeking who have both attacked Egyptian and Israeli forces.