The British-flagged yacht Madleen, which is operated by the pro-Palestinian Freedom Flotilla Coalition (FFC), was aiming to deliver a symbolic amount of aid to Gaza later on Monday and raise international awareness of the humanitarian crisis there.

However, the boat was boarded during the night before it could reach shore, the FFC said on its Telegram account. The Israeli Foreign Ministry later confirmed that it was under Israeli control.

"The 'selfie yacht' of the 'celebrities' is safely making its way to the shores of Israel. The passengers are expected to return to their home countries," the ministry wrote on X. 

All passengers were safe and unharmed, the ministry later added. "They were provided with sandwiches and water. The show is over."

Among the 12-strong crew are Swedish climate campaigner Thunberg and Rima Hassan, a French member of the European Parliament.

"The crew of the Freedom Flotilla was arrested by the Israeli army in international waters around 2 a.m.," Hassan posted on X. A photograph showed the crew seated on the boat, all wearing life jackets, with their hands in the air.

The yacht is carrying a small shipment of humanitarian aid, including rice and baby formula. The Foreign Ministry said it would be taken to Gaza. "The tiny amount of aid that was on the yacht and not consumed by the 'celebrities' will be transferred to Gaza through real humanitarian channels," it wrote.

Israeli Defence Minister Israel Katz ordered the military on Sunday to prevent the Madleen from reaching Gaza, calling the mission a propaganda effort in support of Hamas.

Israel imposed a naval blockade on the coastal enclave after Hamas took control of Gaza in 2007. 

The blockade has remained in place through multiple conflicts, including the current war, which began after a Hamas-led assault on southern Israel on October 7, 2023, that killed more than 1,200 people, according to an Israeli tally.

Gaza's health ministry says over 54,000 Palestinians have been killed since the start of Israel's military campaign. The United Nations has warned that most of Gaza's more than 2 million residents are facing famine.

The Israeli government says the blockade is essential to prevent weapons from reaching Hamas.

The United Nations' special rapporteur on human rights in the Palestinian territories, Francesca Albanese, has supported the FFC operation and on Sunday, urged other boats to challenge the Gaza blockade.

"Madleen's journey may have ended, but the mission isn't over. Every Mediterranean port must send boats with aid & solidarity to Gaza," she wrote on X.