“At 12.23am Maltese time, the Conscience, a Freedom Flotilla Coalition ship came under direct attack in international waters,” the group said in a statement.

“Armed drones attacked the front of an unarmed civilian vessel twice, causing a fire and a substantial breach in the hull,” it added, blaming Israel.

“Israeli ambassadors must be summoned and answer to violations of international law, including the ongoing blockade and the bombing of our civilian vessel in international waters.”

Israel has not commented on the allegation.

The strike, the activists said, appeared to target the boat’s generator.

It left the boat without power and at risk of sinking, the statement added.

There was no indication of any casualties.

The statement said a vessel was dispatched from Cyprus after the aid boat sent out a distress signal, and that Italian authorities said they had sent another boat to the scene.

The group said activists from 21 countries were on board.

They are on what it called a “mission to challenge Israel’s illegal and deadly siege of Gaza, and to deliver desperately needed, life-saving aid”.

Israel has since March 2 blocked all aid deliveries to Gaza, and resumed intense military operations in the territory in mid-March, with a two-month ceasefire in the Israel-Hamas war in tatters.

A previous “Freedom Flotilla” launched from southern Turkey in 2010 ended in bloodshed when Israeli forces stormed the Mavi Marmara vessel, killing 10 and wounding 28.

Hamas’s attack on Israel in October 2023, which sparked the Gaza war, resulted in the deaths of 1,218 people, mostly civilians, according to an AFP tally based on official figures.

The health ministry in Hamas-run Gaza said yesterday that at least 2,326 people have been killed since Israel resumed strikes, bringing the overall death toll since the war broke out to 52,418.