The Gaza-based Hamas movement has said that Israel assassinated its aviation engineer in Tunisia this week.

Mohamed al-Zawari was shot dead outside his home in the southeastern city of Sfax on Thursday.

The Qassam Brigades, Hamas' armed wing, said al-Zawari was one of its commanders and has supervised the group's drone program.

"The Qassam Brigades mourn the martyr of Palestine, martyr of Tunisia, martyr of Arab and Islamic nations and martyr of the Qassam Brigades, Mohamed al-Zawari," the Brigades said in a Saturday statement.

It said al-Zawari had worked with the movement for a decade.

"His assassination is an assault on the resistance and the Qassam Brigades," the group said, vowing to avenge his death.

"The assassination of martyr al-Zawari is a reminder for all Arab and Muslim nations that the Zionist enemy and its agents are roaming free in the region, playing their dirty roles," the statement said.

There was no comment from Israel on the claim.

Tunisian authorities said five suspects have been detained on suspicion of involvement in the killing.

Al-Zawari had returned to Tunisia in 2011 after spending two decades abroad.

"He left Tunisia in 1991 to Libya before moving to Sudan and Syria," Tunisian journalist Borhane Besais told Anadolu Agency.

"In Syria, he cooperated with Hamas' armed wing…to develop its drone program," he said.

Hamas has not offered a proof for its accusation against Israel, but the Jewish state is believed to have assassinated members of Palestinian groups abroad in the past.

In 1997, agents from the Israeli spy agency Mossad attempted to kill Hamas political chief Khaled Meshaal in Jordan by spraying poison into his ear.

Mossad is also believed to have been behind the 2010 assassination of top Hamas commander Mahmud al-Mabhuh in a Dubai hotel.

Israel has never confirmed or denied involvement in his killing.