Israeli forces have seized a charity ship that was trying to break the naval blockade of the Gaza Strip. Activist Greta Thunberg was among the 12-person crew as it headed for an Israeli port on Sunday.

The Freedom Flotilla Coalition, which organized the voyage, said the activists were "kidnapped by Israeli forces" while trying to deliver vital aid to the territory.

The Madeleine was a British-flagged yacht. The Freedom Flotilla Coalition (FFC) said it was intended to deliver symbolic aid to Gaza on Monday and draw international attention to the humanitarian crisis there.

The Israeli Foreign Ministry confirmed that the ship was under Israeli control.

"The 'celebrities' 'selfie yacht' is safely sailing towards the Israeli coast. The passengers will return to their countries," the ministry wrote on Twitter.

The ministry later added that all passengers were safe and sound. "They were provided with sandwiches and water. The show is over."

The yacht carried a small consignment of humanitarian aid, including rice and baby food. The Foreign Ministry said the aid would be transferred to Gaza. "The small amount of aid on board that was not consumed by the 'celebrities' will be transferred to Gaza as a genuine humanitarian "through channels," the ministry wrote.

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