There have been Israeli drone strikes and gun battles between Israeli forces and Palestinian militants in Jenin, after Israel launched a major military operation in the occupied West Bank.
The Israeli military says at least seven militants have been killed.
Palestinian health officials say five people have been killed and 30 injured, according to the report by BBC.
Jenin has seen repeated Israeli military raids in the past year and local Palestinians have been linked to multiple attacks targeting Israelis.
The Israeli military operation, which appears to be one of the most extensive in the West Bank in years, began in the early hours of Monday morning.
Israeli forces used a drone to attack an apartment in the centre of Jenin’s large refugee camp, where some 14,000 people live in an area of only 0.42 sq km (0.16 sq miles).
The military said the apartment was being used as a “joint operational command centre” for the camp and the Jenin Brigades – a unit made up of different Palestinian militant groups including Hamas and Islamic Jihad.
Drones have since been used for further air strikes and thousands of Israeli troops are now believed to be involved in what a military spokesman described as an “counterterrorism operation” focused on seizing weapons and preventing Jenin from acting as a “safe haven” for Palestinian fighters.
The Jenin Brigades said: “We will fight the occupation [Israeli] forces until the last breath and bullet, and we work together and unified from all factions and military formations.”
Ahmed Zaki, a resident of the camp, told the BBC that “columns of Israeli army vehicles penetrated the outskirts of the camp from several streets”.
Palestinian ambulance driver Khaled Alahmad said: “What is going on in the refugee camp is real war.”
“There were strikes from the sky targeting the camp, every time we drive in around five to seven ambulances and we come back full with injured people,” he told Reuters news agency.