Washington (CNN) Don Blankenship, a Republican candidate for US Senate in West Virginia, is defending an ad his campaign released Monday in which he referred to Senate Majority Leader Mitch McConnell as "Cocaine Mitch."

In a press release on Tuesday, Blankenship's campaign claimed McConnell and his family have "extensive ties" to China before elaborating on the reasoning behind the ad.

"His father-in-law who founded and owns a large Chinese shipping company has given Mitch and his wife millions of dollars over the years. The company was implicated recently in smuggling cocaine from Colombia to Europe, hidden aboard a company ship carrying foreign coal was $7 million dollars of cocaine and that is why we've deemed him 'Cocaine Mitch,'" the press release reads.

James Chao, McConnell's father-in-law, was born in China, but moved to the United States before starting the Foremost Group, a shipping company, in New York. The press release points to a 2014 article in The Nation that reported cocaine was found on a ship belonging to Chao's company.

A spokesman for McConnell referred a request for comment on the ad to the National Republican Senatorial Committee and did not respond to a request for comment on the press release. The NRSC did not immediately respond to requests for comment. The Blankenship campaign also did not immediately respond to a request comment.

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