Six Palestinian detainees were sentenced on Sunday to an additional five years in prison for a 2021 escape through a tunnel from a maximum-security jail facility in northern Israel.

The six, already serving life terms for anti-Israeli attacks, escaped on Sept. 6 last year from Gilbao prison through a tunnel dug under a sink.

Hailed as "heroes" by the Palestinians, their escape triggered a massive manhunt by army reinforcements and drones before their capture two weeks later.

Apart from the extra prison sentences, the court also slapped the six prisoners with a fine of 5,000 shekels (nearly $160), the Palestine Liberation Organization (PLO)-run Commission for Detainees and Ex-Detainees' Affairs said in a statement.

"My client told the court he did not regret the escape because he had nothing to lose," one of the prisoners' lawyer, Raslan Mahajana, told reporters.

Five of the detainees are members of the Islamic Jihad group, while the sixth is a member of the Fatah movement of Palestinian President Mahmoud Abbas.

The jailbreak has brought Israel’s prison service under fire and prompted the government to launch an investigation.