The official Kan tv channel quoted the prison service as saying that six prisoners dug a tunnel from which they left Jalboa prison.
The Prison Service said the information was "preliminary, as the circumstances of the incident are under investigation".
Zakaria Zubeidi, a former leader of the Al-Aqsa Martyrs Brigades and a member of Fatah's Revolutionary Council, was among the fugitives, the channel said.
The other five belonged to the Islamic Jihad, the channel said: Fighter Yacoub Nafiat, Mohammed Qassim al-Barda, Yacoub Mahmoud Qadri, Fouad Kmamji, and Mahmoud Abdullah al-Baraa.
Maariv newspaper reported that large police forces were called to the scene, which is currently conducting helicopter searches in the area.
All the escaped detainees are serving life sentences, according to the news site "La".
Haaretz, citing the prison service, said the six escaped prisoners were in the same cell.
The length of the tunnel they had dug was tens of meters long, and the tunnel opening had been discovered a few meters outside the prison walls.
Celebrations spread throughout Palestine after 6 Palestinian prisoners managed to escape through a tunnel dug inside the occupation prisons:https://twitter.com/i/status/1434783296974725123
A senior police official was quoted by private Channel 12 as saying that the escape of prisoners was "one of the most serious security incidents in general".
According to the website of the Addameer Foundation for Prisoner Welfare and Human Rights (Palestinian non-governmental), The Gilboa Prison is located in northern Israel and was established under the supervision of Irish experts and opened in 2004 and is considered "of a very high-security nature and is described as the most guarded prison".
"Following a report from the Prison Service about the escape of six security prisoners from Jalboa prison, large police forces in cooperation with border guards and the Israeli army began an inspection activity and in cooperation with the GSS," the Israeli police said in a statement.
"Security officers in nearby towns have been informed about the escape of prisoners and roadblocks have been set up."
"Meanwhile, a joint operations room has been set up at the scene and police forces have been deployed in the surrounding towns, and special police forces, dogs, and the police helicopter unit are participating in the search."
Hamas and Islamic Jihad praised the escape of prisoners from inside Israeli prisons as "a challenge to the security system."
In a statement, Hamas spokesman Fawzi Barhoum described the escape of the six prisoners from prison as a "major victory."
"This victory proves once again that the will and determination of our prisoners in enemy prisons cannot be defeated or defeated, no matter what the challenges, and that the Zionist enemy has never and will never win, no matter how powerful and powerful it may be."
"The removal of six prisoners of their freedom from Israeli prisons constituted a resounding defeat for the enemy and a major victory for the Palestinian people," The Islamic Jihad said in a statement.
"This heroic operation will deepen the failure and impotence of the occupation and confuse all its calculations," she said.
"Our conflict with the enemy is long and open and the occupation has to understand the lesson, the right does not fall by the statute of limitations... Our people never give up, and they will not raise the white flag at all costs."