Ten Palestinians, including an elderly man and several militants, have been killed during an Israeli military raid in the occupied West Bank, witnesses and Palestinian health officials say.
Explosions and gunfire sounded as troops raided the heart of Nablus, triggering armed clashes with gunmen.
The Israeli military earlier confirmed its troops were operating in Nablus.
Palestinian health officials say a 72-year-old civilian was among those killed outside the besieged house, amid the gun battles.
Video footage showed a body in a street next to bags of bread, in what is usually a busy market area of the old city.
More than 100 people were also wounded by gunfire, according to the health officials. Seven of them are in a critical condition in local hospitals.
A spokesman for Palestinian President Mahmoud Abbas said he condemned the raid and held Israel's government responsible for "this dangerous escalation, which is pushing the region toward tension and an explosion".
Nablus and nearby Jenin have been a focus of search, arrest and intelligence gathering raids that Israel has intensified over the last year amid a spate of deadly Palestinian attacks.
This latest one comes despite reports this week of an understanding brokered by the US aimed at calming tensions.
So far this year, at least 50 Palestinians - including militants and civilians - have been killed, while 11 people have been killed in Palestinian attacks targeting Israelis.