Israeli security forces focused their search on Saturday for the three kidnapped teenagers — Eyal Yifrach, Naftali Fraenkel and Gil-ad Shaar — on wells, water cisterns and caves in the Hebron area.

On the ninth day of Operation Brother’s Keeper to locate the teens, security forces were joined by fire fighters and police specialized in rescue operations.

A significant focus was in the northwestern Hebron area, but security sources said they had no hard leads. They also said the focus on wells and caves did not signify anything definitive as to the well-being of the three kidnapped youths. Israeli officials have stressed that their working assumption is that the three are alive.

Israeli forces are embarked on a massive campaign to locate the trio while simultaneously destroying parts of the Hamas terror infrastructure in the West Bank.

Israeli officials said at least 10 people were detained overnight Friday-Saturday, as forces raided 15 Palestinian charity organization with alleged ties to Hamas. The IDF said it searched over 140 homes overnight.

“Since the beginning of the operation, IDF forces scanned about 1,350 locations in search for the abducted boys, for terrorists and for illegal weaponry. Approximately 340 suspects were detained, out of which 250 terrorists associated with Hamas. Security forces operated against roughly 45 Hamas establishments, ” the IDF said in a statement Saturday.

The Hamas detainees included those who were freed in a 2011 prisoner exchange for Hamas-kidnapped Israeli soldier Gilad Shalit.

Israel has blamed Hamas for the kidnapping and held the Palestinian Authority responsible for the youths’ fate.

“Our activities are an ongoing, combining actions on the ground aimed at locating Eyal, Gilad and Naftali, and systematically targeting Hamas’ terrorists and civilian support system. We remain determined in bringing the boys home and striking the Hamas embodiment on all levels,” said IDF Spokesman Lt. Col. Peter Lerner.

Defense Minister Moshe Ya’alon and IDF chief Benny Gantz met with troops searching for the teenagers Saturday.

Ya’alon reiterated the Israeli government’s working assumption that the teenagers were alive, adding that Israel was extracting a heavy price from Hamas for the abduction.

Earlier Saturday, Palestinian officials said a 60-year-old man died of a heart attack while trying to prevent Israeli troops from searching his house, Israel Radio reported. Palestinian sources said around 30 people were arrested overnight, and that 10 people were injured during a confrontation between Israeli troops and Palestinian rock throwers in Ramallah. Some of the wounded were hit by rubber bullets, others by tear gas, Palestinians said.

An area north of Hebron which was declared a closed military zone on Friday remained cordoned off on Saturday, with soldiers searching house-to-house in the area and no outside traffic allowed in.

A senior Israeli government official said Friday that the noose was tightening around the kidnappers.

Speaking to Channel 10, the official said that, based on security assessments, the teens were still somewhere in the West Bank and their abductors were unsuccessful in moving them in the direction of Jordan, Gaza, or Sinai.

Fraenkel, Shaar and Yifrach were last seen late on the night of Thursday June 12.

Hamas has praised the kidnapping without taking responsibility for it.

AFP contributed to this report.