Past Barnes tweets show Wisconsin Democrat Senate nominee praising Iran ayatollah

Wisconsin's Democratic nominee for Senate Mandela Barnes, is under fire after tweets resurfaced of him praising Iranian Ayatollah Ali Khamenei and questioning U.S. efforts in Syria during the country's civil war.

"The issue of US govt oppression against blacks is a 100s year-old issue. #BlackLivesMatter," Khamenei tweeted on Jan. 1, 2015.

Barnes replied at the time: "The first tweet of 2015 from [Khamenei] is #BlackLivesMatter. Let that sink in. May This be a most wonderful year for you and yours."

Former acting National Intelligence Director Richard Grenell said Barnes is a "radical" and "dangerous" for his online support of Khamenei, whose regime has been accused of serious human rights abuses.

In 2013, Barnes expressed how he wished he could have met Syria leader Bashar al-Assad, similar to how NBA star Dennis Rodman met with North Korean leader Kim Jong-un.

Rodman became friends with Kim after meeting with him several times over the past decade. Kim even released a detained American in 2014 upon a request from the basketball player, ABC News reported.

"I'd like to pull a Rodman next," Barnes tweeted. "I should have hopped that fence to Syria when I had the chance."

International investigators found the government of Bashar al-Assad used chemical weapon in the Syrian Civil War.

Barnes, who is Wisconsin's lieutenant governor, has also been under fire for appearing on Russian state-run outlet RT, The Washington Free Beacon reported.

Wisconsin Republican Sen. Ron Johnson, who's seeking reelection this year against Barnes tweeted Thursday: "Mandela Barnes cannot be trusted with foreign policy in the Senate. He praised Iran’s supreme leader Ali Khamenei, defended [Syrian President] Bashar al-Assad, and went on Russian television to criticize American police officers. He does not have the judgment to be a Senator."

Barnes did not immediately respond to request for comment.