Canadians involved in a Palestinian relief effort expressed outrage at Israel on Saturday, saying activists on a Canadian ship trying to breach the naval blockade of Gaza were beaten by troops who intercepted the vessel.

Israel has said no one was hurt in its takeover of the Canadian-owned Tahrir and an Irish vessel, the Saoirse, on Friday. But members of the group "Canadian Boat to Gaza" claimed otherwise.

Canadian David Heap said in an email early Sunday morning that he had been "Tasered" and "kidnapped" by Israel, and was currently jailed in Givon Prison near the central Israeli city of Ramla.

“Although I was Tasered during the assault on the Tahrir, and bruised during forcible removal dockside I am basically OK,” he wrote.

Heap, from London, Ont. says he saw fellow Canadian shipmates, Ehab Lotayef of Montreal and Karen DeVito of Toronto at the prison Sunday morning, along with other members of the international crew.

"We're calling for their immediate release," group spokesman Dylan Penner said in an earlier interview on Saturday.

The Tahrir, which made a previous failed attempt to reach the blockaded Palestinian territory this summer, was carrying medical aid and activists from nine countries when it was intercepted two days after it set sail from Turkey.

Troops sprayed the vessel briefly with a water cannon before they boarded the ship and towed it to the Israeli port of Ashdod, north of Gaza.

The treatment of activists is a sensitive issue as an Israeli raid on a flotilla in 2010 ended with nine Turkish activists killed.

Israeli officials have said troops took action Friday after repeated calls for the vessels to turn around were ignored, and added that the ships were intercepted peacefully.

Penner expressed frustration Saturday over the limited contact with the detainees.

"This is very concerning on a whole number of levels," said Penner.

Israeli officials said deportation procedures were underway for 22 activists, who were expected to be sent home within 72 hours.

Two Greek crew members were flown home Saturday. Three journalists from the U.S., Spain and Egypt who had been aboard the two ships were also released and told to leave by Sunday.

Israel has said its naval blockade of Gaza, imposed in 2007, is vital to stop weapons reaching the Iran-backed Hamas militants who control the territory. Critics say it amounts to collective punishment.

Israel sees the attempts to break the sea blockade as provocations and publicity stunts. It said the amount of aid in the small boats used by activists is insignificant, as Israel transfers aid to Gaza daily.

But Canadian activists disagreed with that assessment and reaffirmed their intentions to breach the blockade in the future.

"Initiatives like this wouldn't even be necessary if Israel would finally end this illegal blockade and governments like Canada would stop supporting them in that," said Penner.

"The freedom waves are going to keep sailing until the blockade ends."

A spokesman for Foreign Affairs Minister John Baird issued a statement Saturday that said Canadian diplomats are closely watching the situation and are "are liaising with Israeli authorities" in order to provide consular assistance.

Ottawa has warned Canadians against all travel to Gaza, saying the security situation along the coast remains volatile.

Baird has also said Canada can't protect Canadians who break the laws of another country. He urged those wishing to deliver aid to do so through "established channels."

"Unauthorized efforts to deliver aid are provocative and, ultimately, unhelpful to the people of Gaza," he had said in a statement.

Baird also recognized Israel’s right to protect itself and its people from attacks by Hamas and other terrorist groups, including by preventing the smuggling of weapons.