At least ten vessels of the "Global Sumud Flotilla", which seeks to break the blockade on the Gaza Strip, came under repeated drone attacks in the Mediterranean Sea, organizers said.
Explosions were reported and communications on board were severely disrupted, though no casualties have been confirmed so far.
Francesca Albanese, the UN Special Rapporteur on the situation of human rights in the Palestinian territories, said seven drone attacks struck the flotilla after about 15 aircraft flew overhead, stressing the urgent need for international protection.
The flotilla's organizing committee said unidentified objects were dropped on ten boats, causing material damage, while 13 explosions were recorded nearby.
It accused Israel of conducting a media disinformation campaign to justify potential military action against the humanitarian convoy, warning that targeting it would amount to a war crime and a flagrant violation of international law.
The Global Sumud Flotilla comprises humanitarian workers, doctors, artists, and activists from 44 countries. It departed Tunisia earlier this month after several delays, with the aim of establishing a humanitarian corridor and breaking the blockade imposed on Gaza for more than 23 months. Israel previously intercepted similar sea-borne attempts to reach Gaza in June and July.