The Al-Aqsa Martyrs Brigades, a radical offshoot of Palestinian leader Mr Yasser Arafat's Fatah group, claimed responsibility for a Gaza Strip shooting which left an Israeli and the attacker dead.
Witnesses here said militants from the group driving around in a car and shouting through a louspeaker, identified the gunman as Mr Ayman Samir Judeh (22) from the Sheikh Radwan area in the north of Gaza City.
The armed group, which has carried out multiple attacks since January including suicide bombings, also claimed the shooting in a statement sent to the Qatar-based Al-Jazeera satellite channel.
The Israeli was killed when a Palestinian militant opened fire on him and threw grenades at the northern Gaza Strip's Erez border crossing into Israel, Israeli security sources said earlier.
Israeli tanks returned fire, killing the attacker, they added.
A heavy exchange of fire broke out following the deadly exchange, with Israeli tanks firing shells on a Palestinian national security outpost 500 yards away, the Palestinian source said, adding that no casualties were reported.