Hillary Clinton said that tactics implemented by Russia in Crimea are reminiscent of those used by Nazi Germany before World War II.
Speaking at a fundraiser in California, Clinton drew a parallel between Adolf Hitler's rhetoric that ethnic Germans living in neighbouring countries he later invaded were oppressed, and Vladimir Putin's claim that ethnic Russians in Ukraine are under threat by nationalists and radicals.
The former US secretary of State, who is widely expected to run for US president in 2016, particularly criticised Moscow over the issuing of passports to ethnic Russians living in Ukraine's Crimean peninsula.
"Now if this sounds familiar, it's what Hitler did back in the 30s," Clinton said, the Long Beach Press-Telegram reported.
"All the Germans that were ... the ethnic Germans, the Germans by ancestry who were in places like Czechoslovakia and Romania and other places, Hitler kept saying they're not being treated right. I must go and protect my people and that's what's gotten everybody so nervous."
Clinton, 66, made the comment at a $1,500-a-head fundraiser for the Boys and Girls Club of Long Beach.
