International activists left Cyprus for Gaza on Wednesday in a renewed bid to deliver about five tons of donated food and medical supplies to the Palestinian territory despite an Israeli naval blockade.
Free Gaza group organizers replaced a faulty generator on their 66-foot (20-meter) Greek-flagged vessel and set sail from Larnaca port with 21 passengers.
The group aborted the trip to Gaza on Monday after rough weather and engine trouble 40 nautical miles (72 kilometers) southwest of Larnaca forced their return.
The group made an earlier attempt to run the blockade after Israel launched its assault on Gaza late last month in response to rocket fire on Israeli cities. But that trip failed when an Israeli naval vessel collided with the group's boat, which was damaged.
Organizers said Israel has warned the group that it would use "any means" to prevent the boat from reaching Gaza.
Israeli authorities have been notified of the group's mission and that protesters will not be deterred from reaching the Palestinian territory, organizer Huwaida Arraf said.
"Any attack by Israel on the boat will be considered a deliberate attack on unarmed civilians engaged in a humanitarian mission," Arraf said.
Several passengers from the previous attempt, including a Belgian and two Greek lawmakers, opted out of Wednesday's trip, organizers said. Arab doctors who were among the passengers would try to reach Gaza through an overland route.
Arraf said supplies include ventilator parts and basic medicines requested by Gaza hospitals. Among the passengers are a Spanish senator and three doctors from Greece and Britain.
British reconstructive surgeon Sonia Robbins said she felt she had a professional responsibility to reach an unfolding "humanitarian disaster" in Gaza, despite the risks.
"I have a duty to go when the need is there," she told The Associated Press.
Greek orthopedic surgeon Chanent Kampani, who is of Palestinian descent, said traveling to Gaza to help the wounded was the "only way to express ourselves."
"I'm not afraid, we're a peaceful group, we're not hurting anyone," he said.