A suicide car bomber has killed a civilian and wounded 25 Egyptian policemen by driving his car into a security barracks in the city of El Arish, security sources say.
Tuesday's attack is the latest in a string of attacks in the Sinai Peninsula.
The Sinai is home to armed groups who have carried out similar attacks that have killed hundreds of soldiers and police since the army toppled Mohamed Morsi as president in 2013.
A roadside bomb killed three Egyptian soldiers in Sinai on Monday.
Egypt's most dangerous armed group, Sinai Province, is believed to operate in the largely lawless area bordering Israel and the Gaza Strip.
The violence comes just days before an investment conference in the resort of Sharm el-Sheikh that Egypt hopes will project an image of stability and attract billions of dollars.