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TEL AVIV, Israel — Three Jewish teens — including one American — who disappeared while hitchhiking in the disputed West Bank are probably alive, Israel's defense ministers said Saturday.

Israeli Defense Forces said the missing students — Gilad Shaar, 19, Naftali Frenkel, 16, and Eyal Yifrach, 16 — were last seen Thursday night near Gush Etzion, an area that has several Jewish settlements.

"As long as we don't know differently, our assumption is that they are alive," Israeli Defense Minister Moshe Yaalon said in a news conference, adding that the incident had taken officials by surprise.

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Details remain scarce in the teens' disappearance, and there have been no credible claims of responsibility for the kidnappings. Israeli Defense Forces believe the three were abducted by Palestinian terrorists, according to a statement.

Local media reported they were hitchhiking home from their school in the settlement of Kfar Etzion in the West Bank when they disappeared Thursday.

Israeli soldiers were scouring the area, focusing on the community around the restive city of Hebron, Yaalon said.

An Israeli soldier stands guard at a junction near the West Bank city of Hebron on Saturday. Israel was reinforcing troops in the occupied West Bank on Saturday to step up searches for three Israeli teenagers believed to have been abducted by Palestinians.RONEN ZVULUN / Reuters

"We're at the peak of our intelligence and operational efforts. A substantial amount of troops are deployed to the area of Judea and Sumeria" he said, using the biblical name some in Israel employ when referring to the occupied West Bank. "These troops are conducting arrests, which some were already done at night ... and I hope this effort will bring us as soon as possible to the missing as to rescue them alive."

U.S. Secretary of State John Kerry, who brokered peace talks between Israel and the Palestinians before their collapse earlier this year, spoke with Palestinian President Mahmoud Abbas and Israeli Prime Minister Benjamin Netanyahu about the missing teenagers on Friday night.

A Palestinian security official told The Associated Press that Israeli forces had detained more than a dozen people in connection to the case and were examining local security camera footage. The Palestinian official spoke on condition of anonymity because he was not authorized to talk to journalists.

Israel foiled more than 30 attempted kidnappings in 2013, and 14 attempts so far this year, Yaalon said.

— Paul Goldman and F. Brinley Bruton, with The Associated Press