Seven Palestinians have been killed in Gaza and the West Bank, keeping tension high in the besieged Palestinian territories as the citizens of Israel go to the polls.

Four of the deaths came in the West Bank town of Jenin, during an Israeli army raid, Palestinian security sources said.

Israel has imposed a ban on Palestinian travel across the West Bank and Gaza Strip until after the vote on Tuesday because of fears of attacks by Palestinian militants.

Palestinian sources said about 20 Israeli tanks and armoured vehicles rolled into Jenin early on Tuesday.

Palestinian medics said three of those killed in Jenin were involved in an exchange of fire with Israeli troops. A 17-year-old was killed while running to the aid of one of the gunmen.

A Palestinian photographer working for the French news agency AFP, Saif Dahlah, was shot in the leg during the incident.

Mystery blast

Hours earlier, three people were killed in a blast in northern Gaza, at the home of a Palestinian linked to the Islamic group Hamas.

Palestinian security sources said the blast was caused by an Israeli helicopter missile attack, but Israeli security sources denied that such an attack took place in the area.

Israeli radio stations said the blast was caused by the premature explosion of a bomb being prepared by militants.

The three people killed included Mohammed Atel, 30, a bodyguard of Ismail Abu Shanab, a senior Hamas official.

The house belonged to Hamas activist Mohammed Salameh. Two of the dead were his teenage children, a boy and a girl, Palestinians said.

The incident follows a large-scale military incursion into Gaza City by the Israelis on Sunday, when 12 Palestinian militants were killed.

Palestinian officials have accused the Israeli Government of increasing Gaza raids to win further support in the election. However the Israelis say they do not wish to take chances, fearing election day attacks.