Organizers of a flotilla seeking to break Israel’s naval blockade of the Gaza Strip said Thursday that another of their boats had been damaged in port, and they accused Israel of sabotage.

It was the second boat reported damaged in recent days, setting back plans by the pro-Palestinian activists to sail this week.

Fintan Lane, coordinator of a boat that was to carry Irish activists, said the propeller shaft of the vessel had been damaged when it was at a marina in Gocek, on Turkey’s Mediterranean coast. He said a gash in the shaft appeared to have been caused by cutting equipment or a small explosive charge.

“There’s no way this could have happened accidentally,” Lane said by telephone from Turkey. “I think Israel was behind it. No one else has an interest in sabotaging our boat.”

Lane said that the vessel was “out of commission for the flotilla” and that most of its passengers would return to Ireland, while six would join another boat.

He said the damaged shaft had bent during a test run Monday and could have penetrated the hull of the boat at sea, sinking the vessel.

“This was not an attempt to stop our boat leaving its berth. For that, they would have disabled the propeller,” Lane said. “This was delayed sabotage that would have sunk the evidence with us.”

On Monday, organizers said that a boat slated to carry Greek, Swedish and Norwegian activists had its propeller shaft cut while in port in Greece but that it could be repaired in a few days.

An Israeli army spokeswoman had no comment on the reports.

Mark Regev, a spokesman for Prime Minister Binyamin Netanyahu, stopped short of denying the accusations of Israeli involvement.

“There are those who routinely blame Israel for every calamity, and of course they’re not always right,” he said. The flotilla organizers, he added, “are clearly not an objective source of information.”

Israel has said it will stop the flotilla and use force if necessary to prevent the organizers from breaching the naval blockade of Gaza, which is ruled by the militant Islamist group Hamas.

A senior naval officer told reporters recently that although the flotilla was not expected to be carrying arms, allowing the boats through could open the door to more vessels in the future, some of which could be concealing weapons and could not be adequately inspected at sea.

Israeli naval commandos boarded a Turkish ship while intercepting a similar flotilla last year and, after meeting resistance, killed nine activists on board. The incident drew international condemnation and forced Israel to ease its land blockade of the Gaza Strip.

Along with the damage to two of their vessels, organizers of the current flotilla, which was to have included 10 boats, say they have faced administrative obstacles to launching boats from Greece, attributing the delays to pressure from Israel.

Huwaida Arraf of the Free Gaza Movement said that a boat carrying American activists has been delayed after Greek port authorities said they had received a complaint that it was not seaworthy. The boat was inspected this week but has yet to receive authorization to sail, Arraf said. She said a cargo ship carrying aid has also been delayed in port after a reported complaint that it was dumping sewage.

Nitsana Darshan-Leitner, director of the Israel Law Center, a legal-action group that has been trying to obstruct the flotilla, said it had filed a complaint with the Greek coast guard, asserting that authorities there were required to block the departure of vessels engaged in hostile activity against a friendly state.