Tennessee Senator Bob Corker has unleashed a blistering attack on US President Donald Trump, after the two Republicans traded insults on Twitter.

Mr Corker accused the president of lying in a series of television interviews, adding that he debased the US and weakened its global standing.

Mr Trump fired back on Twitter, calling the top Senator a "lightweight" who "couldn't get re-elected".

The pair are due to meet at a Senate lunch to discuss tax reform on Tuesday.

"He is purposely breaking down relationships we have around the world that had been useful to our nation," Mr Corker said on CNN after Mr Trump criticised the senator on Twitter.