The Palestinian Authority’s security forces have arrested more than 100 members of the militant Hamas movement in the occupied West Bank.
It is the biggest such wave of detentions for eight years.
The PA, which is dominated by the rival Fatah movement of President Mahmoud Abbas, said it wanted to prevent Hamas undermining the territory’s security.
A Hamas spokesman said the arrests were an effort to stop a spate of deadly attacks on Israelis in the West Bank.
Husam Badran accused Palestinian security forces of working for Israel and said Hamas held Mr Abbas personally responsible.
The Islamist group, which dominates the Gaza Strip, called for the immediate release of its members and warned of “consequences”.
A spokesman of the Palestinian Authority, Adnan al-Dameri, said those arrested would be put on trial on the charge of threatening security and stability.
“We will not let Hamas undermine our security and draw our country to bloodshed. We will not let Hamas carry out attacks in the West Bank,” he told the Associated Press.
Earlier, Israel’s internal security agency said it had uncovered a Hamas militant cell operating in the Nablus area of the West Bank.
The BBC’s Yolande Knell in Jerusalem says the issue of security co-ordination between Israel and PA security forces remains highly sensitive.
Following the raids, arrest warrants were issued for leading Fatah members in Gaza.
Such developments will raise concerns about renewed divisions between the two factions despite a formal reconciliation deal last year and the creation of a unity government, our correspondent adds.
The two factions had governed separately since Hamas, which won parliamentary elections in 2006, ousted Fatah from Gaza in 2007, leaving the PA governing just parts of the West Bank.
Also on Friday, an Israeli general accused Hamas of providing support to an affiliate of the jihadist group Islamic State in Egypt’s Sinai peninsula.
In an interview with Al Jazeera, Maj-Gen Yoav Mordechai, named members of Hamas’s military wing who he alleged were involved in training militants from the affiliate, known as Sinai Province, and smuggling those wounded in clashes with Egyptian security forces into Gaza for medical treatment.
“We know that Hamas, and I have verified information, that Hamas in Gaza is assisting Sinai Province both in organisation and armaments,” he said.
At least 17 Egyptian soldiers and 100 IS militants have been killed in fighting in northern Sinai since Tuesday, triggered by a co-ordinated mass assault on the town of Sheikh Zuweid by Sinai Province.
And on Friday, several rocket launched from the Sinai Peninsula landed in southern Israel. There were no casualties. Sinai Province said it carried out the attack.
Hamas has repeatedly rejected accusations of collusion with IS and said Gen Mordechai’s comments were an attempt to damage its relations with Egypt.
Hamas has itself faced threats from jihadists. On Tuesday, Palestinian IS militants in Syria threatened in a video statement to topple Hamas in Gaza, accusing it of being insufficiently stringent about enforcing Islamic law.
In a separate development in the West Bank on Friday, an Israeli officer shot and killed a 17-year-old Palestinian who was throwing stones at his vehicle. The Israeli military said the brigade commander had first fired warning shots at the boy.