Israeli forces stopped a Gaza-bound aid boat and detained Greta Thunberg and other activists on board early Monday, enforcing a longstanding blockade of the Palestinian territory that has been tightened during the war with Hamas.

The Freedom Flotilla Coalition, which had organized the voyage to deliver humanitarian aid to the Gaza Strip and protest Israel’s blockade and wartime conduct, claimed that the activists had been kidnapped by Israeli forces.

A pre-recorded message from Thunberg was released after the ship was diverted.

"I urge all my friends, family and comrades to put pressure on the Swedish government to release me and the others as soon as possible, " Thunberg said.

Israel said the passengers would return to their home countries and the aid would be delivered to Gaza through established channels.