One of the 10 ships in the Gaza-bound flotilla has been sabotaged but will be repaired in time for the planned voyage to challenge Israel's naval blockade of the Palestinian territory, activists said Tuesday.

The propeller shaft of the Juliano, a ship shared by Swedish, Norwegian and Greek activists, was cut off while the vessel was docked in the Greek port of Piraeus, according to the Scandinavian organizers.

"Based on a first on-site inspection the damage can be repaired before the planned departure toward the end of this week," said a statement by the Swedish activists, who blamed "hostile divers" for the damage.

In a separate statement, Norwegian delegation leader Torstein Dahle said the incident shows "someone is willing to go to great lengths to stop the flotilla from sailing."

The ship is part of a 10-ship flotilla due to set sail shortly in a bid to break Israel's naval blockade of Gaza. Israel has warned it will thwart any attempt to breach the sea blockade of the Palestinian territory.

Israeli military spokeswoman Maj. Avital Leibovich told reporters Monday that, according to intelligence reports, extremists in the flotilla have supplies of what she called "dangerous incendiary chemicals" to use against Israeli forces.

Dror Feiler, one of the organizers, dismissed those claims, saying the hundreds of people who plan to join the flotilla have signed a declaration of nonviolence.

"No activists on the flotilla are out to harm Israeli soldiers," Feiler told Army Radio on Tuesday. "If they [the Israelis] suspect someone, let them give me the information and we will talk to him. If it turns out to be true, we won't take him on the flotilla. We have no intention of clashing with anyone."

Dire warnings and diplomatic sensitivities shadow the politically charged plan to deliver aid to the Palestinian territory. The looming fear is a reprise of a similar mission a year ago that ended when nine activists on a Turkish vessel died in a raid by Israeli commandos who rappelled on board from helicopters in the pre-dawn darkness.

Several hundred activists, many of them from Europe, Canada and the United States, plan to board the 10 boats, including two cargo vessels carrying medicine and other aid. They say the operation is peaceful.

Two ships, the Louise Michel and the Dignite-Al Karama, carrying a total of 47 activists left from the French island of Corsica on Saturday to join the flotilla.