Israeli authorities have begun detaining hundreds of activists seized from a Gaza-bound flotilla at the southern port of Ashdod on Wednesday, a rights group said, after Israeli forces intercepted their vessels at sea.

The Global Sumud Flotilla set sail from Turkiye last week in the latest attempt by activists to breach Israel’s blockade of the Palestinian territory, after Israeli forces intercepted a previous convoy last month.

Israeli authorities said 430 activists aboard the flotilla were en route to Israel, while rights group Adalah said some had already arrived at Ashdod port and were being held there.

“Having set sail toward Gaza to deliver humanitarian aid and challenge the unlawful blockade, these civilian participants were forcefully abducted from international waters and taken into Israeli territory entirely against their will,” Adalah said.

“These acts are a direct extension of Israel’s policies of collective punishment and starvation of Palestinians in Gaza.”

The Israeli foreign ministry dismissed the operation as a publicity stunt serving Hamas.

“Another PR flotilla has come to an end. All 430 activists have been transferred to Israeli vessels and are making their way to Israel, where they will be able to meet with their consular representatives,” a spokesman from Israel’s Ministry of Foreign Affairs said late on Tuesday.

“This flotilla has once again proved to be nothing more than a PR stunt at the service of Hamas,” the spokesman added.

Prime Minister Benjamin Netanyahu earlier denounced the flotilla as “a malicious scheme designed to break the blockade we have imposed on Hamas terrorists in Gaza”.

The US on Tuesday sanctioned four people associated with the Global Sumud Flotilla and accused them of being “pro-terrorist”.

Around 50 ships had departed from southwestern Turkiye on Thursday. A website tracking the flotilla’s location later showed several vessels being intercepted west of Cyprus.

Nine Indonesian citizens who were part of the flotilla “have all been reported arrested by Israel”, a spokeswoman for Indonesia’s foreign ministry said, citing information dated Wednesday.

Indonesia called on Israel to immediately release all vessels and crew members, adding that “every diplomatic channel and consular measure will continue to be fully utilised”.

Saad Edhi, the son of prominent social worker Faisal Edhi and the grandson of late philanthropist Abdul Sattar Edhi, is among the activists detained. Indonesian newspaper Republika earlier said two of its journalists were among the nine Indonesians detained.

Turkiye and Spain have condemned the interception.

Organisers said the flotilla also included 15 Irish citizens, including Margaret Connolly, sister of President Catherine Connolly.

South Korean President Lee Jae Myung on Wednesday said Israel had arrested South Korean nationals in international waters, calling the action way out of line.

In a cabinet meeting, Lee said the South Korean citizens had been detained for reasons not valid under international law, questioning whether such actions could be allowed to pass without protest.

Lee said he believed many European countries were willing to arrest Netanyahu under International Criminal Court warrants, but that Seoul must make its own judgment on the matter.

On Tuesday, Pakistan and nine other countries issued a joint statement condemning Israel’s interception of the flotilla. The joint statement by the foreign ministers of Pakistan, Turkiye, Bangladesh, Brazil, Colombia, Indonesia, Jordan, Libya, Maldives and Spain was shared by the Foreign Office on the social media platform X.

It said that the ministers “condemn in the strongest terms the renewed Israeli assaults against the Global Sumud Flotilla, a peaceful civilian humanitarian initiative aimed at drawing international attention to the catastrophic humanitarian suffering of the Palestinian people”.

Israel controls all entry points into Gaza, which has been under an Israeli blockade since 2007.

During the Gaza conflict, the territory has suffered severe shortages of food, medicine and other essential supplies, with Israel at times halting aid deliveries entirely.

A previous flotilla attempt was intercepted last month in international waters off Greece, with most activists expelled to Europe.