Donald Trump calls on Bernie Sanders to consider independent bid

US Republican presidential candidate Donald Trump (L) and Democratic Senator Bernie Sanders

US Republican presidential front-runner Donald Trump has called on his Democratic rival Senator Bernie Sanders to run as an Independent in the 2016 presidential race.

“Bernie Sanders has been treated terribly by the Democrats—both with delegates & otherwise. He should show them, and run as an Independent!” Trump said in a tweet on Tuesday.

Trump made the comment after the Vermont senator complained in a Sunday’s interview with NBC News channel, about his unfair treatment at the hands of the Democratic Party.

When asked if the party had been fair to him, Sanders responded, “No. I think we have — look, we're taking on the establishment. That's pretty clear.”

"The fact that we had debates that were scheduled — pretty clearly, to my mind — at a time when there would be minimal viewing audience, et cetera, et cetera. But you know, that's the way it is. We knew we were taking on the establishment. And here we are. So not complaining," he added.

Jane Sanders, the Democratic candidate’s wife, who was interviewed following Trump’s tweet, stated that her husband will not “play the role of spoiler” by running as an Independent.

"The reason that he was active and he decided to run in the Democratic Party was just that: We cannot afford a Republican in the White House. We cannot afford a Republican appointing Supreme Court justices. So Bernie will not be running as an independent," she continued.

Sanders also stressed that he will continue to run as a Democrat.

In another tweet earlier this month, Trump also pointed out to the unfair treatment of Sanders, saying, “week after week — he wins, he wins, he wins, he wins — then I watch you and I watch all of the pundits and they say ‘but he can’t win.’ You know why? It’s stacked against him. It really is. It’s stacked against him. In his case it’s super delegates, in my case it’s the obvious.”

The real estate mogul, who has criticized the Republican nominating process as "rigged," has occasionally cited Sanders' deficit in the Democratic delegate fight as an example of how both parties' systems are corrupt.

An independent bid by Trump himself has been much speculated about in the course of the 2016 race, with the businessman fluctuating on his claims of loyalty to the GOP.