Two men blew themselves up in Egypt's north Sinai today, one near an airport used by an international observer force, security sources said.
A spokesman for the Multinational Force and Observers (MFO) group which supervises the Israeli-Egyptian peace treaty said the first bomber appeared to target its vehicles but there were no MFO injuries.
The second man blew himself next to a police car outside a police station in Sheikh Zuwayed, near the northern coast town of El Arish.
The car was empty and there were no other casualties, the security sources said.
In a third incident in the east of the Nile Delta on Wednesday, gunmen ambushed police, leading to an exchange of fire, police sources said.
They had no immediate information on the outcome of the skirmish and it was not clear if the incidents were related.
On Monday three bombs in the resort of Dahab on the east coast of Sinai killed 18 people and injured scores.
The Dahab explosions resembled other attacks attributed to a Sinai-based group which has bombed two other resorts on the east coast over the last two years.
The same group is thought to have carried out a bombing that damaged an MFO vehicle in Sinai in August, slightly injuring two Canadians.
The first suicide bombing today was near the MFO camp at El Gorah, about 35 km from El Arish and close to the site of the attack in August.
The MFO, which has contingents from 11 countries, was set up to supervise security provisions in the 1979 peace treaty. It patrols the Egyptian-Israeli border to ensure that the treaty is observed.