The Palestinian Islamic Jihad terror group sent gunmen to the Jenin refugee camp in the West Bank on Tuesday ahead of expected Israeli raids hunting six security prisoners who escaped from an Israeli prison, as the fugitives remained at large over a day after their disappearance.

Israel has launched a massive manhunt to capture the six prisoners, who are considered highly dangerous, after they broke out of the high-security Gilboa prison early Monday in what is considered to be among the most serious jailbreaks in the country’s history.

Five of the six fugitives are members of Palestinian Islamic Jihad.

The terror group has issued several threats to Israel since the escape, warning against raids in Jenin and against taking action against the group’s members in Israeli prisons.

“If the IDF enters [Jenin] it will be met with significant firepower from many weapons and explosive devices,” the group said at a Tuesday press conference in Jenin.

Palestinian Islamic Jihad and Fatah both dispatched members to Jenin to bolster their forces there ahead of the expected incursions by the Israel Defense Forces, Channel 12 news reported.

PIJ militants hold a press conference in Jenin tonight, amid the intense manhunt for the six Palestinian security prisoners, originally from Jenin, who fled Gilboa Prison on Monday. pic.twitter.com/JRbl9HZAiP

— Emanuel (Mannie) Fabian (@manniefabian) September 7, 2021

The six escapees include Zakaria Zubeidi, a notorious commander in Fatah’s Al-Aqsa Martyrs Brigade terror group, who was in prison while on trial for two dozen crimes, including attempted murder.

Zubeidi’s brother Jibril, who said he was held for seven years in Gilboa Prison, told Channel 13 he had believed the jail to be impregnable; he also said he had “no idea” of his Zakaria’s whereabouts.

Four escapees were in jail for life in connection with deadly attacks against Israelis and affiliation with the Palestinian Islamic Jihad terror group. The remaining prisoner was being held in administrative detention and had not been charged with a crime other than belonging to the Palestinian Islamic Jihad.

Many Palestinians assume that some, or all, of the six escapees would seek refuge in the Jenin camp. All of the fugitives are from the Jenin area, which has largely become a no-go zone to the IDF and Palestinian Authority security forces.

Video posted by Palestinian media said to be from Jenin showed masked gunmen walking down a city street, firing weapons in the air.

#شاهد انتشار للمقاومين داخل مخيم جنين. pic.twitter.com/T8AcaU9yC9

— وكالة شهاب للأنباء (@ShehabAgency) September 6, 2021

West Bank residents overwhelmingly support the fugitives, according to widely quoted assessments Tuesday. Their escape is viewed as a “landmark, strategic” success that will embolden extremist Palestinian groups, Channel 12 said.

Public celebrations have been reported in the West Bank cities of Nablus and Hebron, and in the Gaza Strip, following the escape. The festivities in Jenin at the humiliation of Israel have been particularly prolonged and widespread.

Palestinian Authority Prime Minister Mohammad Shtayyeh spoke out in support of the fugitives, saying, “It’s the right of every prisoner to escape from prison by any means.”

Channel 13 news reported that police successfully retraced the route the men took shortly after fleeing the prison, and had not found any evidence that the men crossed any of Israel’s borders as of Tuesday night, indicating they were likely inside Israel or the West Bank.

The IDF believes that the six men split up to better evade capture, and may be armed, the report said.

The military has bolstered its forces on the Gaza border due to fears some of the escapees may try to reach the Palestinian enclave. A victory celebration with the fugitives and the leadership of the Hamas terror group would likely inflame an already tense Gaza, TV reports noted.

Palestinians carry a poster of the Islamic Jihad terror group, reading in Arabic: “The second great escape from the prisons of the Zionist enemy – 1987 Saraya Prison – 2021 Gilboa Prison,” following the escape of six Palestinians from an Israeli prison, in the Jenin refugee camp in the northern West Bank, on September 6, 2021. (JAAFAR ASHTIYEH / AFP)

A senior source with the Israel Police told the Walla news site that there was some possibility that at least some of the fugitives would try to reach the Strip. “From the police’s perspective, every possibility is on the table,” the source said.

Palestinian Islamic Jihad warned earlier on Tuesday that if there was any change to the conditions of prisoners being held in Israeli jails, especially its members, following the prison escape, it would respond.

“Harming the prisoners is a red line, and the occupation must carefully consider what we say and realize that we are ready and able to protect our prisoners by all means,” the terror group said in a statement.

“Every act of revenge on prisoners will bring the opening of the gates of hell against Israel in every place,” it added.

The Israel Prisons Service on Tuesday moved hundreds of Palestinian Islamic Jihad prisoners between facilities and imposed new restrictions, Channel 12 reported.

Israeli troops patrol along the security fence in the village of Muqeibila, near the northern West Bank city of Jenin, on September 6, 2021, following the escape of six Palestinian security prisoners from an Israeli prison. (Jalaa Marey/AFP)

The escape has sparked tumult in Israel’s prison system. Senior officials from the prison were summoned for questioning on Tuesday evening, the Kan public broadcaster reported. Earlier in the day, at least 14 Prisons Service staff were questioned by the police amid suspicions that the escapees may have had assistance.

Prison officials and police are being widely castigated for lapses that facilitated the escape, with a litany of blunders allowing the breakout to occur in the first place, and a failure to grasp the severity of the situation for several hours after it occurred.

Authorities said that they had not achieved any breakthroughs in the search for the terrorists as of Tuesday evening, but Hebrew and Palestinian reports said that three suspects had been arrested on suspicion of helping the fugitives.

Police entered the neighboring Arab towns of Na’ura and Tamra, located northeast of Afula, and searched mosques. Numerous checkpoints were placed in the area.

The three suspects were arrested in Na’ura, reports said. The detainees were suspected of helping the six break out of the prison or flee the area afterward.

Authorities believe at least some of the escaped prisoners stopped in the town for a short time after their breakout and changed clothes there, Haaretz reported.

Police officers and prison guards inspect the scene of a prison escape outside the Gilboa prison in northern Israel, Monday, Sept. 6, 2021. (AP/Sebastian Scheiner)

Police were also conducting searches in the Palestinian town of Jalamah, adjacent to the West Bank border fence, and near the Palestinian city of Jenin, the Walla news site reported.

The IDF also deployed additional troops to the border with Jordan, as authorities suspected some of the fugitives would attempt to flee to Israel’s eastern neighbor.

Authorities suspect that the fugitives split up following the escape from Gilboa prison. They ran some 3 kilometers (1.9 miles) after exiting the hole dug underneath the prison walls, police officials said. There, some of them boarded a getaway vehicle, Channel 12 reported.

The six escaped via a tunnel in their cell’s drainage system, though officials said that a security flaw meant that they did not need to excavate to create a passage out.

Security officials are most concerned that the six men could carry out a terrorist attack against Israeli civilians, though leading figures have indicated that it is unlikely.