Italian prosecutors have opened an unlawful detention investigation following a raid by Israeli forces on a Gaza-bound aid flotilla, Italian media reported on Monday.

The probe was opened following complaints received over the detention last week of Spanish citizen Saif Abu Keshek and Brazilian Thiago Avila, who were on an Italian-flagged vessel.

An Israeli court on Sunday extended for two days the detention of the two activists who were taken to Israel for questioning.

The two were on a flotilla of more than 50 vessels that left France, Spain and Italy, aiming to break Israel’s blockade of Gaza and bring supplies to the devastated Palestinian territory.

They were intercepted in international waters off Greece on Thursday, with Israel saying it had removed some 175 activists.

Avila and Abu Keshek were taken to Israel for questioning, while the other activists were released.

The Israeli operation was widely criticised, particularly by Italy and Spain.

The Rome prosecutor’s office opened a similar investigation last October following a previous attempt by a humanitarian flotilla to reach Gaza.

In that incident, several hundred activists, including Swedish climate campaigner Greta Thunberg, were detained at sea, transferred to Israel and then expelled.