Vladimir Putin, who has carved out a health nut image by wrestling with tigers or judo opponents, raised eyebrows Thursday as he was pictured swollen-faced and caked in make-up, apparently to mask a black eye.

Journalists feverishly speculated that the Russian premier could have taken a punch during a judo session or even had a facelift, after he visited Ukraine on Wednesday slathered in war paint.

Israel's deadly raid on an aid flotilla for Gaza was a tragedy that demands detailed investigation and must not be repeated, Russian Prime Minister Vladimir Putin told Agence France Presse in an interview.

"What is especially tragic is that this act was carried out in neutral waters," the Russian prime minister said in a discussion late Monday in the Black Sea resort town of Sochi.

Israel on Wednesday was discussing the format of an investigation into its deadly raid on a Gaza-bound flotilla, but Prime Minister Benjamin Netanyahu insisted soldiers would be off-limits.

Israel was in talks with "several members of the international community" about the investigation, Netanyahu said, stressing that it should focus on "the pro-Palestinian activists who fought the naval commandos with knives and clubs."