NATIONWIDE — Hillary Clinton, the 2016 Democratic nominee for president, has a strong message for her 2020 counterpart: Do not concede "under any circumstances." 

The former Secretary of State cited her belief that the final results of the election could "drag out" due to mail-in voting, namely Republicans' percieved efforts to disrupt the U.S. Postal Service. 

"Joe Biden should not concede under any circumstances because I think this is going to drag out, and eventually, I do believe he will win if we don't give an inch and if we are as focused and relentless as the other side is," Clinton said in an interview on Showtime's "The Circus."

Speaking to her campaign's former communications director, Jennifer Palmieri, a contributor to "The Circus," Clinton echoed her remarks from last week's Democratic National Convention: "As I said in my speech, you can win 3 million more votes and still, you know, not get elected because of the Electoral College. It all comes down to the Electoral College." 

Clinton alleged that Republicans "have a couple of scenarios that they are looking toward," including "messing up absentee balloting."

"They believe that helps them so that they then get maybe a narrow advantage in the Electoral College on Election Day," she said, mentioning recent elections in Wisconsin and Michigan to stress the importance of protecting mail-in voting.

"So, we've got to have a massive legal operation," Clinton added, "and I know the Biden campaign is working on that."

In his remarks to delegates at the Republican National Convention on Monday, Clinton's former opponent, President Donald Trump, accused Democrats of attempting to use the coronavirus pandemic to steal the election, repeating a claim he made at a rally in Wisconsin earlier this month that the only way Democrats can win is “if this is a rigged election.”

He doubled down on his attacks on mail-in voting later that day in an exclusive interview with Spectrum News.

"I'm concerned it's just not a fair situation," Trump said. "It's fraught with error and fraud and problems.

"If you look at what's happening, it's a disgrace, it's a disaster," the president told Spectrum News 1's Tim Boyum. "The best thing is to go to a voter booth and vote."

State elections officials say that’s not true, and the president made similar claims about a "rigged election" in 2016 until he won.