Israeli forces in the occupied West Bank killed five Palestinians including a militant on Monday, in a raid that saw eight Israeli security personnel wounded and rare helicopter fire.
Palestinian authorities reported "intense gunfire" by Israeli forces in what the army described as "routine activity" in which an armoured vehicle was said to have been hit by a "dramatic" explosion.
The Palestinian health ministry said five people had been killed and at least 91 others were wounded in the violence.
It identified those killed as 15-year-old Ahmed Saqer, as well as 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 militant group.
Among the injured was Palestinian journalist Hazem Nasser, who was hospitalised with a gunshot wound, according to the Palestinian journalists syndicate.
The sound of gunfire was heard across Jenin as wounded Palestinians continued to arrive by ambulance to the northern West Bank city's Ibn Sina hospital into the early afternoon, an AFP journalist said.
Crowds, among them Palestinian gunmen, gathered outside a government hospital in Jenin for the funerals of those killed in 11 hours of fighting.
Jenin's deputy governor, Kamal Abu al-Rub, told AFP the Israeli forces had launched the raid at around 4am (0100 GMT).
"The army stormed the (Jenin refugee) camp and the city after the dawn prayer in large numbers, and there was intense gunfire," he said.
Jenin camp resident Bassem Talib, 38, said he "woke up to the sounds of gunfire at 4.15 in the morning".
"The army targeted anything that moved... there is no safety," he said.
An AFP journalist at the scene said Israeli forces withdrew from Jenin at around 1510 (1210 GMT).
'Deteriorating situation'
The Israeli army said an armoured vehicle had been hit by a "very unusual and dramatic" explosive device at around 7.10am (0410 GMT), during "routine activity" to arrest two "wanted suspects" – one affiliated with Islamist movement Hamas and the other with Islamic Jihad.
"We had five Israeli border police guys wounded, and two soldiers also lightly wounded," army spokesman Richard Hecht said.
The army said an Apache helicopter had fired missiles in support of the soldiers during an operation to extract the injured.
A Palestinian intelligence official told AFP on condition of anonymity 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.
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.
Violence in the Israeli-Palestinian conflict has escalated over the past year, particularly since the hard-right government of Prime Minister Benjamin Netanyahu took power in December.
'Open war'
Hussein al-Sheikh, the Palestinian Authority's civil affairs minister, said a "fierce and open war is being waged against the Palestinian people".
Speaking as the raid unfolded, Israeli Defence Minister Yoav Gallant said: "We will use all the tools at our disposal and strike terrorists wherever they may be."
The raid came as the US State Department's top Middle East official, Barbara Leaf, was in Ramallah to meet with the Palestinian leadership.
Hamas leader Ismail Haniyeh and Islamic Jihad chief Ziyad al-Nakhalah were also in Tehran for talks with Iranian leaders Monday.
Israel has occupied the West Bank since the 1967 Six-Day War and its forces regularly launch incursions into Palestinian cities, which are nominally under the control of president Mahmud Abbas's Palestinian Authority.
Later Monday, two Israeli soldiers were wounded after Palestinians rammed them at a checkpoint near Jenin, the army said.
"The soldiers responded with fire, hits were identified," a statement said.
The Palestinian health ministry said two Palestinians suffering gunshot wounds were being treated in a Jenin hospital, one of them in a critical condition.
Jenin and its adjacent refugee camp – which was besieged by the army in 2002 and saw deadly fighting – have frequently been the site of violent clashes.
In March, four Palestinians were killed during a raid on the camp.
Ten Palestinians were killed in another operation in the camp in January – at the time the deadliest single raid in the West Bank for 20 years. An incursion into Nablus the following month killed 11 Palestinians.
Since the start of the year, at least 164 Palestinians, 21 Israelis, a Ukrainian and an Italian have been killed in violence linked to the Israeli-Palestinian conflict, according to an AFP tally compiled from official sources.
The figures include combatants as well as civilians and, on the Israeli side, three members of the Arab minority.