At least five Palestinians were killed in an Israeli military operation in the West Bank city of Nablus, the Palestinian Authority's Health Ministry said on Tuesday.
The ministry said that around 20 other people were injured in the operation. It added that a sixth Palestinian was shot dead in overnight clashes at the village of Nabih Saleh, north of the West Bank administrative center of Ramallah.
According to Palestinian sources, the 31-year-old suspected leader of the "Lions' Den" militant group was killed in the raid.
The Israeli Defense Forces (IDF) said that the flat that was the target of the operation had served as an explosives store. An IDF statement said that the explosives were detonated by soldiers.
According to the IDF statement, dozens of Palestinians burnt tires and threw stones at Israeli troops, who returned fire after being shot at.
Israel holds the Lions' Den responsible for the death of an Israeli soldier two weeks ago and a failed attack in Tel Aviv. Two days ago, a member of the group was killed in a bomb explosion remotely activated by the IDF.
How did leaders react?
Palestinian president Mahmoud Abbas is establishing "urgent contacts in order to stop this aggression against our people," presidential spokesman Nabil Abu Rudeinah said.
Hamas chief Ismail Haniyeh warned that the violence would "plunge Palestine into escalation."
Israeli Prime Minister Yair Lapid said that Palestinian militants "need to know that we will reach them wherever they are."
"Israel will never stop acting for its security and we will do what needs to be done," Lapid said. "The goal is to reduce terrorism and ensure that it does not affect Israeli citizens."
Israel is set to hold legislative elections on November 1.
Prime Minister Lapid said that its fighters were involved in "violent clashes" with Israeli forces and threatened reprisals for the operation.
Some Lions' Den members are also affiliated with Abbas' Fatah party, Hamas or Islamic Jihad.
More than 100 Palestinian fighters and civilians have been killed since the start of the year, according to the United Nations. This is the highest death toll in seven years.