Four Palestinians have been killed and several others were injured in a mysterious blast in the south-east part of the Gaza Strip, Gaza's health ministry said.
The explosion struck a three-wheeled vehicle on Saturday near one of the five protest camps the Palestinians have set up along the volatile Gaza-Israel border in recent weeks.
The reason for the explosion near the city of Rafah was not immediately known. The Israeli military said it has no information on the blast.
Thirty-five Palestinians have been killed by Israeli fire since the mass border protests began on March 30, including 28 who have been shot dead.
Gaza's ruling militant Hamas group is organising the protests to promote the Palestinian refugees' "right of return" to Israel, but it is also driven by the dire living conditions.