Israeli military incursions into Gaza and the West Bank have continued overnight, killing and injuring dozens.

A dozen people were reported killed during an air raid early on Wednesday in Gaza’s second-largest city Khan Younis. At least five Palestinians were killed and a senior Fatah leader was arrested in overnight raids in the occupied West Bank.

At about dawn, Israeli forces targeted two residential buildings in Khan Younis in the south of Gaza, where many have sought refuge after the Israeli army ordered the evacuation of the northern part of the besieged territory.

Medical sources told Al Jazeera 12 people died in the attack, and that more than two dozen were wounded.

Multiple Israeli raids were also staged overnight in the West Bank, where at least five more Palestinians were killed, bringing the death toll in the region to 130 since October, the Palestinian health ministry said.

The largest raid took place in the Jenin refugee camp, in the north of the West Bank, where at least three Palestinians were killed.

“It began around midnight and ended around 7am and was, by far, one of the largest raids we’ve seen since October 7,” Al Jazeera’s Imran Khan reported from Ramallah.

“The Israeli army came in large numbers,” Khan added. “We’re hearing at least 100 troops and multiple armoured vehicles.”

A senior leader of Fatah, a moderate Palestinian rival of Hamas, was also arrested during the raid. Khan called the detention “unusual”.

“Since October 7, the concentration by the Israeli army has been on Hamas leaders and activists within the occupied West Bank,” our correspondent said. “So this arrest will have Fatah leaders here in Ramallah very concerned. The family says during the arrest he was beaten up before being taken away.”

Elsewhere, an elderly man was killed by Israeli forces in the occupied West Bank district of Tulkarm early on Wednesday, according to Palestinian media.

The Wafa news agency identified the man killed as Magdy Zakaria Youssef Awad, 65, who was shot by Israeli forces during confrontations with residents of Tulkarm refugee camp in the occupied West Bank. According to the agency, Awad was a physically impaired elderly man.

According to Al Jazeera’s Khan, at least 30 people have been arrested in the raids, but the number is likely to rise once the Palestinian Prisoners Society collates final figures.

Al Jazeera Arabic has also reported armed confrontations between Israeli forces and Palestinians in Qalqilya, in the northwest of the West Bank.

North of Hebron, 16-year-old Abdullah Mohammad Meqbel was shot dead after Israeli forces fired live ammunition at a group of demonstrators who had taken to the streets to denounce Israel’s deadly attacks on Gaza.

The West Bank has suffered increasing levels of violence amid the Israel-Hamas war, including from attacks by Israeli settlers.

In reaction, Palestinians declared a general strike across the territory on Wednesday.

“The most important thing we demand is to stop injustice and tyranny, to stop killing innocent people, and refrain from arbitrary revenge,” 26-year-old Ramallah resident Fakhri Muhammad Shreiteh told AFP.

Continued bombardment, communications blackout

The raids came as humanitarian groups denounced Israel’s deadly attack on the Jabalia refugee camp in Gaza, renewing their calls for an immediate ceasefire.

The Israeli military said it targeted Hamas infrastructure in the camp “that had taken over civilian buildings”. Women and children were seen being rescued from those buildings that were still standing near a massive crater, in footage shot live by Al Jazeera Arabic at the scene.

Palestinian fighters and Israeli forces engaged in heavy fighting in the Zeitoun neighbourhood, located southeast of Gaza City, an Al Jazeera correspondent reported. Shelling continued in northern Gaza as Israeli incursions continued to the north and northwest of the Gaza Strip and the south and southeast of Gaza City.

Al Jazeera’s Hani Mahmoud, reporting from Khan Younis, said the Strip was plunged into a near-total communications blackout just after midnight on Wednesday, the second such incident since last week.

“The difficult part about this is the inability of knowing exactly what is going on,” Mahmoud said. “It’s becoming increasingly difficult to understand the situation in the northern part of the Gaza Strip.

So far, at least 8,525 people have been killed in Gaza since the war began, including 3,542 children – more than have died in conflicts around the world in each of the last four years.

More than 1,400 people have died in Israel, mostly in the deadly Hamas attack on October 7.