The Israeli army reblocked the main north-south road in the Gaza Strip Thursday morning, after saying that a rocket attack on a Jewish settlement violated a truce, a Palestinian official told AFP.

Three Palestinians were wounded by live bullets when Israeli troops posted near the road opened fire on cars piling up at a checkpoint, Palestinian security sources and witnesses said.

"The Israeli army informed Palestinian officials of the closure of the southern part of this road. Two barricades were set up near the Israeli settlement of Kfar Darom and the Gush Katif settlement bloc following the firing of rockets overnight in this area," the official said.

Israel earlier formally protested to the Palestinians over a violation of a truce recently announced by Palestinian militant groups, following the firing of three rockets on Kfar Darom in an attack which slightly wounded three people.

Israeli troops stationed near Gush Katif further south then fired on angry drivers blocked at the al-Matahen checkpoint, Palestinian security sources said.

Three of them were wounded, hospital sources in the nearby city of Khan Yunis said.

Following the incident, Israeli troops dragged concrete blocks on the road at the Abu Gholi and al-Matahen checkpoints, respectively in the central and southern Gaza Strip, trapping cars between the two, witnesses said.