Israeli soldiers detain a Palestinian man during a military campaign to search for three missing Jewish teenagers in the West Bank city of Hebro. Photo: Reuters/Mussa Qawasma

Israel sent more troops to the occupied West Bank yesterday to step up searches for three Israeli teenagers believed to have been abducted by Palestinians, with a military source saying it was not known if they were dead or alive.

The three boys disappeared on Thursday night after they left a Jewish settlement bloc where they were seminary students.

Since then the Israeli army has carried out house-to-house searches, round-ups and interrogations in the nearby Palestinian city of Hebron and outlying villages.

They arrested at least 12 Hebron area residents, including two women, confiscated video from privately owned security cameras and prevented around 300 residents from leaving the area, Palestinian officials and witnesses said.

The suspected kidnapping is a test for ties between Israel and Palestinian President Mahmoud Abbas, which were badly frayed by his power-sharing deal in April with Hamas, Islamists who are hostile to the Jewish state.

On Friday, the US State Department said that, at its urging, Abbas was “working closely together” with Israel to resolve the crisis, drawing censure from Hamas.

A military source said Israel was working on the assumption that the missing three boys – two 16-year-olds and the third a 19-year-old civilian – were abducted by Palestinians.

To escalate the searches, Israel was bringing a “significant” number of fresh forces to the Hebron area, including a paratrooper brigade, the military source said.

“We need more boots on the ground to deal with this serious development. We need to be able to track them down, we need to use all of the capabilities at our hands in order to bring this to a quick end.”

Defence Minister Moshe Yaalon told reporters that Israel’s “working assumption” was that the three were still alive. Yet the Israeli military source said: “We can’t confirm if they are alive or dead. We don’t know at this time.”

Yaalon said Israel had foiled 14 attempts by Palestinians to abduct its citizens this year.

“It seems that this event got in under our radar.”

A Palestinian security source said Abbas’s forces were helping Israel in the search, drawing condemnation from Hamas, which praised those behind the suspected kidnapping as “heroes”.

“Security coordination between (Palestinian Prime Minister Rami) Hamdallah’s and Abbas’s security services and the enemy to locate the heroes of the Hebron operation and arrest them is a moral stain,” said Hamas spokesman Fawzi Barhoum.

Palestinian militants have said in the past that they want to kidnap Israelis to win concessions from the Israeli government. More than 1,000 Palestinian prisoners were freed in 2011 in exchange for the release of an Israeli soldier held captive in the nearby Gaza Strip for more than five years.