The 57-year-old Belgian originally from the port of Antwerp was on board a small boat that left Turkey with six other people -- an Italian, another Belgian, a Malaysian, a Finn, a Canadian-Palestinian and a South African.

About 10 members of the Israeli forces intercepted them in international waters more than 500 kilometres (310 miles) from the Israeli coast on Monday, he said as he arrived at Istanbul airport on Thursday.

Turkey has evacuated 422 people on special flights, including 85 of its own citizens, and deployed doctors and ambulances.

"They first jammed communications then boarded in broad daylight with guns and fired plastic bullets just for fun," said Cabral.

"We found out we were the 12th ship intercepted.

"We were surprised. There were corvettes all around us. They moved in with a lot of violence even though we all had our hands in the air."

Cabral said the Israelis were marine commandos. "We know them," he added.

- 'Punch to the temple' -

"I was the second in command on the boat. Our captain, an Italian, was still standing and they targeted him straight away. I took a punch to the left temple," Cabral recounted.

"Then they transferred us, still using violence, our hands bound with plastic ties onto this prison-ship, into containers.

"I heard them say in English, 'let's have some fun'."

Cabral said the detainees asked to see a doctor for three days but were always told "later, later".

"They confiscated the medication of one person who suffers from epilepsy. On board the boat 'Sirius', seven people had 35 fractures between them," he added, pointing to his ribs and arms.

On board, the soldiers threw down from the upper deck boxes filled with bread and water "but not in sufficient quantity", he said.

"There must have been 200 of us... We asked for more water, toilet paper, tampons for the women. We had to ask for everything."

The detainees were taken off the ship on Wednesday and taken in cramped prison vans to be locked up near Ashdod, in southern Israel.

Cabral said the handcuffs were "far too tight" and the detainees were bent double for hours on end.

"We couldn't see anything. They pressed on our necks," he said.

"And they kept on slapping us, insulting us... People were laughing with them, playing the Israeli national anthem. They were particularly harsh with the Jordanians, the Tunisians."

On Thursday morning, they were finally transferred to Ramon airport near Eilat, in Israel's south.

"There again, we were subjected to insults."

- "We're going to carry on' -

Cabral is hoping to return to Belgium on Friday after seeing one of the doctors waiting for the evacuees. He also said he intended to leave again on the next flotilla.

"Absolutely. We're going to carry on," he said.

Bilal Kitay, a Turkish national from Bingol, a mainly Kurdish city in eastern Turkey, held his wife in his arms.

This was his second trip with the "Flotilla for Gaza", on board a boat with about 10 other activists.

He insisted that their interception by Israeli forces was "much, much more violent than the previous one" in April.

"They attacked us," he said. "Each of us was beaten, women and men... It's what Palestinians experience all the time," he said.

"Unfortunately, they treat their animals better. They alone consider themselves human," he said. Kitay is also planning to leave on the next convoy.