A Palestinian boy stands next to Israeli soldiers as they take part in an operation to locate three Israeli teens near the West Bank City of Hebron. Picture: Ammar Awad

Jerusalem - Israeli troops detained 37 Palestinians in the West Bank during the night as its arrest campaign entered its 11th day on Monday, with no sign of three teenagers thought kidnapped by Hamas.

Since the youths disappeared from a hitchhiking stop in the southern West Bank on June 12, Israel has been rounding up hundreds of Palestinians in a bid to find them, while also dealing a crushing blow to the Islamist movement's West Bank network.

But with tensions rising among the Palestinian population over the crackdown which has seen four Palestinians killed by troops over the past week, commentators believe the campaign is about to shift focus to intelligence gathering rather than mass arrests.

“Overnight, the forces detained 37 suspects and searched 80 locations, specifically in the area north west of Hebron, Beit Awwa (southwest of Hebron) and also in (the northern city of) Jenin,” a spokeswoman said.

So far, troops have arrested 361 people, among them 250 Hamas members and 57 who were freed during a 2011 prisoner swap deal to secure the release of Gilad Shalit, a soldier held in Gaza for five years by Hamas, the army said.

Despite the operation, there has been no claim of responsibility and no sign of the missing youngsters, although military spokesman General Motti Almoz said on Sunday that all information indicated they “are alive”.

Pundits said Operation Brother's Keeper was “nearing its end in the present format” and would be refocused ahead of the start next week of the Muslim holy month of Ramadaan.

“The defence establishment is troubled by the increase in the number of Palestinian casualties and the possibility that the confrontations will spill over into the month of Ramadan, which starts in less than a week,” wrote Haaretz defence correspondent Amos Harel.

“The IDF (army) would likely prefer to significantly reduce the size of its deployment and return to more focused intelligence gathering,” he said, indicating that the military was likely to encounter problems in mustering enough evidence to put many of the detainees on trial.

Yediot Aharonot ran a similar story saying that within days the focus would be on more searches and fewer arrests.

“The IDF will focus on looking for the kidnapped teenagers in the Hebron sector and the Etzion (settlement) bloc, but arrests will be cut back significantly,” the paper said.

There was no immediate comment on the reports by the army.

Palestinian president Mahmud Abbas has denounced the abductions and defended his security forces' ongoing cooperation with their Israeli counterparts to try to locate the missing boys.

But there are growing signs of Palestinian frustration with their own security forces, with angry protesters hurling rocks a Ramallah police station early on Sunday, smashing the windows of two police cars.

Israeli rights groups on Sunday wrote to Defence Minister Moshe Yaalon to denounce the crackdown which they branded “collective punishment” and a violation of basic rights. - AFP