Organizers of a Gaza-bound flotilla carrying symbolic aid and pro-Palestinian, anti-Israel activists said late Tuesday they heard explosions and saw multiple drones that targeted some of their boats, currently situated off Greece.

“Multiple drones, unidentified objects dropped, communications jammed and explosions heard from a number of boats,” the Global Sumud Flotilla said in a statement, without adding whether there were any casualties.

“We are witnessing these psychological operations firsthand, right now, but we will not be intimidated,” the statement said.

German flotilla member Yasemin Acar said in a video she posted on Instagram that five vessels had been attacked.

“We are carrying only humanitarian aid,” she said. “We have no weapons. We pose no threat to anyone. It is Israel who is killing thousands of people (and) starving a whole population.”

In an earlier video, Acar said the activists had “sighted 15 to 16 drones,” adding that their radios had been jammed as loud music could be heard.

One video posted by the flotilla’s official Instagram page showed an explosion it said it recorded from the Spectre boat at “01:43 GMT +3.”

In another video posted by the same page, Brazilian activist Thiago Avila said four boats had been “targeted with drones throwing devices” just before another explosion was heard in the background.

The Global Sumud Flotilla set sail from Barcelona earlier this month with the aim of breaking Israel’s blockade of Gaza and delivering aid to the territory.

It currently numbers 51 vessels, most of which are situated off the Greek island of Crete.

It had already been targeted in two suspected drone attacks in Tunisia, where its boats had been anchored before resuming their voyage towards Gaza.

Among its high-profile participants is environmental activist Greta Thunberg.

Israel said Monday it would not allow the boats to reach Gaza, accusing the flotilla of serving the Hamas terror group.

“This flotilla, organized by Hamas, is intended to serve Hamas,” the Foreign Ministry writes on X. “Israel will not allow vessels to enter an active combat zone and will not allow the breach of a lawful naval blockade.”

“If the flotilla participants’ genuine wish is to deliver humanitarian aid rather than serve Hamas, Israel calls on the vessels to dock at the Ashkelon Marina and unload the aid there, from where it will be transferred promptly in a coordinated manner to the Gaza Strip,” the statement said.

“Israel urges the participants not to break the law and to accept Israel’s proposal for a peaceful transfer of any aid they might have,” it added.

Israel blocked two earlier attempts by activists to reach Gaza by sea in June and July.

Israel has come under huge international pressure over its war in Gaza, which was sparked by the October 7, 2023, Hamas massacre that killed some 1,200 people and saw another 251 taken hostage.

The war has sparked a dire humanitarian crisis in the Strip, with most of the population displaced.