Swedish rights activist Greta Thunberg has accused Israel of "kidnapping" her Gaza-bound aid flotilla in international waters and committing a crime, speaking to reporters after arriving in Paris following her deportation on June 10.

The Swedish climate activist, who has become a pro-Palestinian campaigner, said upon landing: "They kidnapped us in international waters and committed a crime, but this is nothing compared to the genocide happening in Gaza."

Thunberg claimed Israeli authorities tried to make the activists watch "propaganda videos" but said she refused to look. "This is nothing compared to what's happening in Gaza, which desperately needs humanitarian aid," she told reporters at Charles de Gaulle Airport.

The 22-year-old activist responded to Defence Minister Israel Katz's claims that the flotilla was a publicity stunt, calling it "ironic that they say this, given their own propaganda videos."

Thunberg and 11 other activists were detained June 9 after Israeli naval forces intercepted their UK-flagged vessel Madleen near Gaza's territorial waters. The group had sailed for nine days attempting to deliver humanitarian aid to the blockaded territory.

The ship was towed to Ashdod port, where Israeli authorities processed the activists for deportation. Those refusing to sign deportation documents were to be brought before judicial authorities under Israeli law.

Katz said the activists were shown footage of Hamas's October 7 attacks upon arrival but "refused to continue watching when they saw what it was about."

"The antisemitic flotilla members close their eyes to the truth, proving again they prefer murderers over victims," Katz added.

Israel maintains its 18-year naval blockade of Gaza is necessary for security, whilst critics argue it constitutes collective punishment.