Ron Paul claimed he didn't get the endorsement of Donald Trump because he was the only Republican presidential "candidate that didn't kiss his ring."

Paul hit at his GOP rivals for meeting with the billionaire real estate mogul in 2011, the State Column reports. Mitt Romney, who met with Trump in late September but denied media access to the encounter, received Trump's endorsement Feb. 2, just days ahead of the 2012 Nevada Caucuses.

In an interview with Fox 13 News, Paul downplayed the value of Trump's endorsement, saying he "can't imagine why anybody talks about him."

"I don't think he has that much credibility," Paul said. "I never went up to see him. I don't understand why people pay any attention to him."

This isn't the first time Paul has jabbed Trump. He released an earlier statement asking "why anyone would care" about Trump's endorsement of Romney.

Paul also refused to participate in a Trump-moderated debate in early December, calling it "wildly inappropriate." Trump's debate appearance was eventually canceled.

Trump caused confusion this week when reports initially surfaced that he would endorse Newt Gingrich in the Republican presidential race. Trump's eventual endorsement of Romney carried an element of surprise considering Trump's history of bashing Romney.