Israel refers to the five dead as "terrorists" and says they were hiding in a mosque in the city of Tulkarm, which is located on the northwestern border of the occupied territory with Israeli territory.
The Israeli military says there were exchanges of fire and that one person was also arrested.
One of the five people killed is accused of having been involved in planning violent attacks against Israelis. The man was a known local commander of the Islamist group Islamic Jihad, who was also reported to have been killed in an Israeli operation earlier this year – but he later unexpectedly appeared at the funeral of other militants and was carried out by jubilant crowds.
The man's death is also reported by the Palestinian news agency Wafa.
Total number of dead
Israeli raids on the West Bank are not uncommon, but they rarely target multiple locations at the same time. Under the night to Wednesday, the Israeli military launched a coordinated attack on several locations in the Palestinian territory: Jenin, Nablus, Tubas and Tulkarm.
A total of 16 Palestinians have been killed in these raids, according to consistent reports from Wafa and the Red Crescent. The Islamist movement Hamas has identified several of the dead as combatants.
Violence on the occupied West Bank has increased alongside the war in Gaza. The Israeli military has made regular incursions and Israeli settlers have attacked several times. Since last October, more than 660 Palestinians have been killed there.
"Opening an eastern front"
According to the Israeli government, the new "anti-terror operation" on the West Bank is motivated by the fact that armed Islamist groups are gathering to "open an eastern front against Israel" with the help of Iran.
"We must handle this threat in the same way as we handle the terrorist infrastructure in Gaza, including temporary evacuation of Palestinian residents and any measures that may be required," wrote Israel's Foreign Minister Israel Katz on social media on Wednesday.
From the Palestinian side, Israel is accused of wanting to drag the West Bank into war.
UN Secretary-General António Guterres wants Israel's "large-scale military operation" to stop immediately. His spokesperson emphasizes that Israeli forces must "exercise maximum restraint and only use deadly force when absolutely unavoidable".
Named after the situation west of the Jordan River. Has an area of 5,860 square kilometers – equivalent to roughly three Vättern. The West Bank is therefore 16 times larger than the Gaza Strip.
About 3 million Palestinians live on the West Bank, but also several hundred thousand Israeli settlers.
The 1990s Oslo Accords divide the West Bank into three areas: A, B and C. In A and B, which together account for about 40% of the area, the Palestinians have some self-governing authority. In C, Israel has control. According to the Oslo Accords, the Palestinians were to gradually gain more power and control, even in area C. But this has not happened, and Israel has instead expanded its domains, built new settlements, roads and barriers.
Israel's grip on the West Bank began with the capture of the area during the Six-Day War in 1967. Since then, it has been under military occupation pending a final peace agreement. However, there are also strong right-wing forces in Israel that believe the country has the right to large parts of or the entire West Bank.
The Palestinian self-government on the West Bank is led by the secular Fatah party.
