"@ilduce2016: 'It is better to live one day as a lion than 100 years as a sheep,' - @realDonaldTrump #MakeAmericaGreatAgain," the Republican front-runner shared from a parody Twitter account.
The website Gawker claimed credit for creating the parody account about Il Duce, which translates to 'the leader' in Italian.
The Gawker website said it had created "a Twitter bot that would post quotes from the writings and speeches of... Mussolini" at Trump until he eventually retweeted one yesterday. The parody account's profile picture is a composite of Trump's hair and Mussolini's face.
"It's a very good quote. It's a very interesting quote...I know who said it. But what difference does it make whether it's Mussolini or somebody else?" Trump said.
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Asked whether he wanted to be associated with Mussolini, he said, "No, I want to be associated with interesting quotes. Hey, it got your attention, didn't it?"
Mussolini led Italy from 1922 until 1943. The fascist dictator led the country into war with the US in 1941.
Some conservative critics of Trump's rhetoric about use of power, both in the US and abroad, have suggested that his declarations fall along the lines of fascist oratory.
Also yesterday, Trump appeared reluctant to distance himself from an endorsement from David Duke, a former senior leader of the white supremacist group Ku Klux Klan.
He told CNN that he "didn't know anything about David Duke".
Later, however, he tweeted a video from an earlier press conference in which he appeared to recognise Duke's name immediately and said, "David Duke endorsed me? OK, I disavow".
It is not the first time Trump has shared controversial tweets with his nearly 6.5 million followers.