Donald Trump has called climate activist Greta Thunberg "a strange person" and recommended she attend "anger management class" following her involvement in a Gaza-bound aid flotilla intercepted by Israeli forces.

"She's a young, angry person," the US President said. "I don't know if it's real anger, it's hard to believe, actually. But I saw what happened. She's certainly different."

Trump added: "I think she has to go to anger management class. That's my primary recommendation for her."

The President's remarks came after Thunberg claimed she had been "kidnapped" whilst aboard an aid vessel attempting to break Israel's naval blockade of Gaza.

Donald Trump criticised Greta Thunberg

"She said she was kidnapped by Israel? I think Israel has enough problems without kidnapping Greta Thunberg," Trump said.

The 22-year-old Swedish activist was amongst 12 people aboard the Madleen, operated by the Freedom Flotilla Coalition, which departed Sicily on 1 June carrying humanitarian supplies for Palestinians in Gaza.

The vessel was attempting to deliver essential items including baby formula, flour, rice, nappies, sanitary products, water desalination equipment, medical supplies, crutches and prosthetic legs for children.

Israeli Defence Minister Israel Katz had pledged to prevent the ship reaching its destination, stating he had "instructed the IDF to act so that the Madleen... does not reach Gaza."

PICTURED: Israeli forces hand out sandwiches to 'freedom flotilla' sailorsREUTERS

The activists had planned to reach Gaza's territorial waters within a week of departure.

Israeli forces intercepted the vessel in international waters, with crew members reporting their tracking and communication devices were being jammed approximately 160 nautical miles from Gaza.

Thunberg released a pre-recorded video before the interception, stating: "My name is Greta Thunberg, and I am from Sweden. If you see this video, we are being intercepted and kidnapped in international waters by the Israeli occupational forces, or forces that support Israel."

She urged "all my friends, family and comrades to put pressure on the Swedish government to release me and the others as soon as possible."

Donald Trump used his presser to slam the activist

Israeli Defence Minister Katz dismissed the activists as "Hamas propagandists" and directed particularly harsh words at Thunberg.

"To the antisemitic Greta and her fellow Hamas propagandists — I will say this clearly: You should turn back, because you will not make it to Gaza," he stated.

Also aboard was Rima Hassan, a French MEP of Palestinian descent who has been barred from entering Israel due to her opposition to Israeli policies.

Thunberg, who turned 22 in January, first gained international prominence in 2018 when she began her solitary climate strike outside the Swedish Parliament at age 15.

Her protest sparked the global Fridays for Future movement, which saw millions of students worldwide join weekly climate strikes.

Speaking from the relief ship before its interception, Thunberg told Middle East Eye that governments had "disappointed the Palestinian people" and left it to ordinary individuals to act.

"We cannot sit by and allow this to happen. We are watching... a genocide happening, following decades and decades of systematic oppression, ethnic cleansing, occupation," she said.

The activist, who has Asperger's syndrome, has previously addressed the UN and inspired what became known as the "Greta effect" on public climate awareness.