Palestinians take cover during a raid by Israeli forces outside a hospital in the West Bank city of Jenin on Monday. Associated Press

Israeli forces in the occupied West Bank killed five Palestinians on Monday, in a raid that saw seven Israeli security personnel wounded and rare helicopter fire.

The sound of gunfire was heard across Jenin as wounded Palestinians continued to arrived by ambulance to the northern West Bank city's Ibn Sina hospital into the early afternoon, a  journalist said.

Crowds, among them Palestinian gunmen, gathered outside Jenin government hospital, as the funerals of those killed in eleven hours of fighting began.

The Palestinian health ministry said five people had been killed and at least 91 others were wounded in the violence.

It named four of those killed: 15-year-old Ahmed Saqer, Khaled Assassa, 21, Qais Jabareen, 21, Ahmad Daraghmeh, 19, and Qassam Abu Saria, 29.

The Palestinian Islamic Jihad claimed Abu Saria as a fighter for the group.

Among the injured was Palestinian journalist Hazem Nasser, who was hospitalised with a gunshot wound, according to the Palestinian journalists syndicate.

Jenin's deputy governor, Kamal Abu Al Rub, told reporters that the Israeli forces had launched the raid at around 4:00 am.

"The army stormed the (Jenin refugee) camp and the city after the dawn prayer in large numbers, and there was intense gunfire," he said.

A journalist at the scene said Israeli forces withdrew from Jenin at around 15:10.

The Israeli army said an armoured vehicle had been hit by a "very unusual and dramatic" explosive device at around 7:10 am, during "routine activity" to arrest two "wanted suspects" -- one affiliated with Hamas movement and the other with the Islamic Jihad.

"We had five Israeli border police guys wounded, and two soldiers also lightly wounded," army spokesman Richard Hecht said. "From that point, we had to extract our injured."

"It will take a few hours, it's going to be pretty harsh, there is a lot of fire," he added in the early afternoon.

The army said that an Apache helicopter had fired missiles in support of the soldiers, a rare move in the West Bank.

A Palestinian intelligence official told reporters on condition of anonymity that it was the first time since 2002 -- during the second Palestinian intifada, or uprising -- that the Israeli army has fired missiles from an aircraft during a raid in Jenin.

The United Nations rights chief, Volker Turk, said he was "extremely worried by the deteriorating situation."

"Unlawful killings of Palestinians by the Israeli security forces have increased, including apparent extrajudicial executions," he added.

Palestinian health minister Mai Al Kaila called in a statement for the "urgent" dispatch of blood and medical supplies to Jenin.

Hussein Al Sheikh, the Palestinian Authority's civil affairs minister, said a "fierce and open war is being waged against the Palestinian people... by the occupation (Israeli) forces."

He called for the Palestinian leadership to take "unprecedented decisions" without elaborating.