Greece will guarantee the safe sailing of boats currently in its waters as part of an international flotilla heading to Gaza, its foreign minister said on Thursday, adding that Athens had informed Israel that Greek citizens were in the flotilla.

The Global Sumud Flotilla is using about 50 civilian boats to try to break Israel’s naval blockade of Gaza. Many lawyers and activists, including Swedish climate campaigner Greta Thunberg, are on board.

“There are a small number of boats currently in the waters of Crete, and we will guarantee the safe sailing,” Giorgos Gerapetritis told Reuters in an interview on the sidelines of the U.N. General Assembly.

“We have already informed the Israeli government about the participation of Greek citizens in this, and we will make sure that everything goes well.”

Israel has repeatedly criticised the flotilla, accusing its activists of complicity with the Hamas militant group.

Italy sent a navy ship to the flotilla’s assistance after the vessels were attacked by 12 drones in international waters 30 nautical miles (56 km) off the Greek island of Gavdos.

Gerapetritis said Athens was not planning to join Italian and Spanish naval ships at this stage.

He played down the drone incident, but said there would be a full inquiry to determine what happened.

“At the moment, it seems that it is safe, but we are on full alert about it,” he said.