At least eight Palestinians were killed and dozens of others injured as Israel launched one of the largest military raids in the last two decades on occupied West Bank's Jenin on Monday.

The sounds of gunfire and explosives could be heard across the city hours after the strike and drones were clearly audible overhead, the Jenin Brigades, an armed group based in the city's large refugee camp, said it was engaging the Israeli forces.

At least six drones could be seen circling over the city and the adjoining camp, a densely packed area that houses around 14,000 people in less than half a square kilometer.

Operations of this scale have rarely been seen in the city since the end of the second Intifada uprising two decades ago.

"What is going on in the refugee camp is real war," said Palestinian ambulance driver, Khaled Alahmad. "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."

The Palestinian Health Ministry confirmed at least eight people had been killed and 80 wounded in Jenin, while another man was killed in the city of Ramallah after being shot in the head at a checkpoint.

The Israeli military claimed its forces targeted a building that served as a command center for the Jenin Brigades in the West Bank.

Until last month, when it carried out a strike on June 21 near Jenin, the Israeli military had not used drone strikes in the West Bank since 2006.

The apparent scale of Monday's raid, involving a force described as "brigade-size" – suggesting around 1,000-2,000 troops – underlined Jenin's place in Israel's recent strategy to curb armed groups including Hamas, Islamic Jihad and Fatah.

But the growing violence could trigger a wider response from the Palestinians, drawing in groups in the Gaza Strip, the coastal enclave controlled by Hamas.

"The resistance will confront the enemy and defend the Palestinian people and all options are open to strike the enemy and respond to its aggression on Jenin," said a statement from the Islamic Jihad group in Gaza.

Protests flare in Jenin

As daylight broke on Monday in Jenin, thick black smoke from burning tires set alight by protesters, residents swirled through the streets while calls to support the demonstrators rang out from loudspeakers in mosques.

A spokesman for Palestinian President Mahmoud Abbas called the operation "a new war crime against our defenseless people."

The Israeli military alleged the targeted building functioned as an "advanced observation and reconnaissance center," as well as a coordination and communications hub for the armed groups.

It provided an aerial photograph showing what it said was the target and which indicated the building hit was near two schools and a medical center.

Only days before last month's drone strike, the army used helicopter gunships during a raid that killed five Palestinians.

The escalating violence in the West Bank over the past 15 months has caused mounting international alarm, with regular army raids in cities like Jenin, a series of deadly attacks by Palestinians against Israelis, and rampages by Jewish settler mobs against Palestinian villages.

Israel captured the West Bank, which the Palestinians see as the core of a future independent state, along with East Jerusalem and Gaza, in the 1967 Middle Eastern war. Following decades of conflict, peace talks that had been brokered by the United States have been frozen since 2014.