Ten Palestinians were killed during a raid by Israeli troops in the occupied West Bank on Wednesday.
The rare, daytime arrest operation in Nablus also saw more than 100 Palestinians wounded, according to officials.
The raid, which reduced a building to rubble and left a series of shops riddled with bullets, was one of the bloodiest battles in nearly a year of fighting in the West Bank and east Jerusalem.
Several of those killed outside were civilians, including two elderly men, while 102 people were wounded, Palestinian officials said.
The Israeli operation, coupled with the high death toll, raised the prospect of further bloodshed.
A similar raid last month was followed by a deadly Palestinian attack outside a Jerusalem synagogue, and the Hamas militant group warned on Wednesday that “its patience is running out.”
The Israeli military said it entered Nablus on Wednesday to arrest three wanted militants suspected in previous shooting attacks in the West Bank, including the killing of an Israeli soldier last fall.
The military usually conducts raids at night in what it says is a tactic meant to reduce the risk of civilian casualties.
It said it took advantage of a rare window of opportunity after intelligence services tracked down the men in a hideout and warned they posed an imminent threat.
The army said it surrounded the building and asked the men to surrender, but instead they opened fire. When one of the militants tried to flee the building, he was shot and killed, said Lt Col Richard Hecht, a military spokesman.
The military then fired missiles at the house, he added, leaving it in ruins and killing the other two men.
A recently formed armed group based in the Old City of Nablus called the Lion’s Den, which has surged in prominence over the past months, confirmed the militants were its members.
During the raid, the military said armed men in the city “shot heavily toward the forces,” which responded with live fire. It said others hurled rocks and explosives at the troops.
The military released a video taken from inside an armored vehicle as crowds of Palestinian youths pelt it with stones. There were no Israeli casualties.
The Palestinian Health Ministry said 102 people were wounded, and six of them were in critical condition.
Various Palestinian militant groups claimed six of the dead — including the three from Lion’s Den targeted in the raid — as members. But two men, aged 72 and 61, were also killed.
There was no immediate word on whether the others belonged to armed groups.
The fighting comes at a sensitive time, less than two months after Israeli Prime Minister Benjamin Netanyahu’s new hard-line government took office. The government is dominated by ultranationalists who have pushed for tougher action against Palestinian militants.
In the Gaza Strip, a spokesman for the ruling Hamas militant group issued a veiled threat following the Nablus raid.
“The resistance in Gaza is observing the enemy’s escalating crimes against our people in the occupied West Bank, and its patience is running out,” said Abu Obeida, a spokesman for the group.
Late on Wednesday, Palestinian activists burned tires along Gaza’s frontier with Israel in protest.
Hamas has battled Israel in four wars since seizing control of Gaza in 2007, and Israeli officials have expressed concerns about rising tensions ahead of the Muslim holy month of Ramadan, which begins in the second half of March.
Israel says the military raids are meant to dismantle militant networks and thwart future attacks while the Palestinians view them as further entrenchment of Israel’s open-ended, 55-year occupation.
Israel captured the West Bank, east Jerusalem and the Gaza Strip in the 1967 Mideast war, territories the Palestinians seek for their hoped-for independent state.
