Top Swedish crime writer Henning Mankell accused Israel of "piracy" during its attack on a Gaza-bound aid fleet and denied weapons were stashed on the ships.

• Henning Mankell released from Israeli prison

Mankell, the author of the popular Wallander series of detective novels, said Israeli commandos shot people who were sleeping during Monday's raid on the flotilla, in which nine activists were killed and dozens injured.

"The Israelis transformed their navy into a pirate enterprise," Mankell told reporters after he returned to the southwestern Swedish city of Gothenburg late Tuesday after taking part in the aid operation.

"All the ships (in the flotilla) were hijacked, and this was really piracy," said Mankell, whose comments were broadcast by Swedish public radio Wednesday.

"What will happen next year when we come back with hundreds of boats? Will they fire a nuclear bomb?" he asked.

Mankell was one of 11 Swedes who participated in the operation, which involved a total of 682 people from 42 countries aboard six ships.

He and three others who were aboard the flotilla, including member of parliament Mehmet Kaplan, arrived in Sweden Wednesday.

The seven others were on their way from Israel to Istanbul, where they would spend the night before flying to Sweden Thursday, foreign ministry spokesman Tobias Nilsson told AFP.

Swedish Foreign Minister Carl Bildt, in Istanbul for a conference, would try to meet the Swedes at their arrival in Turkey, his press secretary said.

Mankell said the passengers "had expected to run into trouble when we reached the border (of Israeli territorial waters), but we were mistaken." "Far from the limit, in (international) water, we were attacked... by helicopters, speedboats and other vessels and lots of commando soldiers who came onboard and hijacked ship after ship.

"They did not hesitate to attack using lethal force. They shot people who were sleeping," he said.

Mankell said the Israelis' claim that large numbers of weapons were found on the vessels was "nonsense."

"On the ship I was on, they found one weapon: my razor. And they actually came up and showed it off, my razor, so you see what level this was at," Mankell said.

The author further accused Israel of kidnap when it towed the ships to one of its ports and detained those on board.

"At the moment they started taking the boats towards Israel, we were all kidnapped. It is that simple," he said.

Despite the aid flotilla's failure to break Israel's blockade against the Gaza Strip and deliver some 10,000 tonnes of supplies, Mankell said the operation was a partial success.

"Today we know that Israel is on its knees. No one could predict that the rest of the world would react in this way. They are completely isolated," he said, adding "people are completely fed up with this brutality and this violence that the power (Israel) has on its conscience."

He said he was in "despair" over the killings and added that he was also saddened to think of "some of our friends who are still sitting in some very uncomfortable prisons in Israel, where they are being beaten."

Swedish Foreign Ministry spokesman Tobias Nilsson told AFP seven other Swedes who were participating in the flotilla were on their way to from Israel to Istanbul, where they would spend the night before arriving in Sweden Thursday.

Swedish Foreign Minister Carl Bildt, in Istanbul for a conference, was hoping to meet the Swedes at there arrival there, his press secretary said.

Israel said Wednesday the hundreds of activists detained on the boats and diverted to Israel had all been released for deportation. The activists were all taken to Tel Aviv airport or the Jordanian border.