JERUSALEM -- Israel warned Monday it would exact a heavy price from Hamas, as a massive search for three missing Jewish seminary students turned into the widest crackdown on the Islamic militant group in the West Bank in almost a decade.
Israel has blamed Hamas for the apparent abductions, without providing proof, and has arrested more than 150 Palestinians since the three teens disappeared in the West Bank late Thursday.
Most of those rounded up were from Hamas, including activists and political leaders, among them 10 members of the non-functioning Palestinian parliament. Israel's Security Cabinet discussed further steps Monday, reportedly including the possible deportation of Hamas leaders from the West Bank to the Gaza Strip, where Hamas is in control.
Defence Minister Moshe Yaalon said Hamas has begun "paying a heavy price, both in terms of arrests and assets," suggesting the aim is to try to dismantle the Hamas infrastructure in the West Bank. It's not clear how far Israel will go, though, considering the risk of a conflagration in the West Bank after several years of relative calm.
Meanwhile, Israeli Prime Minister Benjamin Netanyahu has used the abductions to try to discredit Western-backed Palestinian President Mahmoud Abbas and the unity government Abbas formed with Hamas backing earlier this month.
Netanyahu claimed Abbas is ultimately responsible for the fate of the teens and alleged the Palestinian leader's new alliance with the Islamic militants created an atmosphere that encouraged the apparent kidnapping.
Abbas and Netanyahu spoke by phone Monday, a rare contact between the two. Netanyahu's office said the Israeli prime minister asked Abbas for help with the search.
"The Hamas kidnappers came from territory under Palestinian Authority control and returned to territory under Palestinian Authority control," Netanyahu told Abbas, referring to the areas where Palestinians have limited self-rule.
Abbas aides have rejected Netanyahu's contention, saying Israel is in overall control of the West Bank. The junction where the teens were last seen is under full Israeli security control and is commonly used by soldiers and settlers.
Abbas condemned both the apparent kidnapping and a "series of Israeli violations" in a statement Monday. He referred to the arrests and the killing of a 20-year-old Palestinian by Israeli army fire early Monday, during a confrontation between stone throwers and soldiers in a West Bank refugee camp.
Despite the pitched rhetoric, Palestinian security officials have worked with Israeli counterparts to try to locate the missing teens, Palestinian officials said.
Abbas has said such security co-ordination in the West Bank -- in place since Hamas seized the Gaza Strip from him in 2007 -- would continue even under a unity government. The joint efforts have routinely targeted Hamas activists.
The Israeli search for the missing students -- two 16-year-olds and a 19-year-old -- was concentrated in and around Hebron, the largest Palestinian city in the West Bank. Troops sealed the area, blocking access roads, and conducted house-to-house searches.
Arrests of Hamas activists began shortly after the teens disappeared. Several dozen more were rounded up overnight, including Abdel Aziz Dweik, the speaker of the parliament and a senior Hamas figure in the West Bank.
Hamas is considered a terror group by Israel and the West because of past attacks that have killed hundreds of Israeli soldiers and civilians.
Over the years, Israel has carried out periodic campaigns against the group, including arrest sweeps, but the current crackdown is the widest in the West Bank since 2006, when Israel retaliated for the capture of an Israeli soldier by Hamas-allied militants in Gaza. Separately, Israel has carried out several major offensives against Hamas in Gaza.
Israel has not provided evidence of Hamas involvement in the disappearance of the teens.
Israeli government spokesman Mark Regev said Monday that Israel waited for 48 hours before pointing the finger at Hamas. "The information is conclusive," he said. "The people behind the abduction are Hamas members."
Asked about Israel's claim, U.S. State Department spokeswoman Jen Psaki said that while Hamas has used similar tactics in the past, "I don't want to jump to a conclusion" at this time.
Hamas has praised the apparent abduction, but has stopped short of claiming responsibility. Other claims have emerged, including from a purported al-Qaida branch, but could not be authenticated.
Netanyahu said it could take time to track down the missing students, adding that "we are in the midst of a complex operation."
Officials have said they are working on the assumption the teens are alive, but four days without a sign of life is raising concerns.
The apparent abductions came at a time when Israeli-Palestinian tensions were already running high over the Palestinian unity government. Some senior Israeli officials called for a crackdown not just on Hamas, but also on Abbas' Palestinian Authority.
The incident has put Abbas in a bind.
He has repeatedly assured the U.S. and Europe that security co-ordination with Israel would continue under a unity government. But because such co-operation with Israel is widely unpopular among Palestinians, he cannot use it to counter Netanyahu's charges against him and the unity government. Highlighting it publicly could torpedo Palestinian reconciliation efforts.
Psaki, the State Department spokeswoman, signalled Monday that the apparent abductions have not changed Washington's view of the unity government.
"Based on what we know now, we do not believe that Hamas plays a role in the government," Psaki said.
Palestinian militants have repeatedly threatened to kidnap Israelis, hoping to use them as bargaining chips to win the release of prisoners held by Israel. No demands have been issued in connection with the disappearance of the three Israeli teens, however.
Currently, dozens of Palestinians held by Israel are on a hunger strike to try to force Israel to end the practice of "administrative detentions" without charges or trial.
