Trump tried unsuccessfully to open Moscow Trump Tower complex during 2016 election

Even as he campaigned for president, Donald Trump and his business associates were trying to open a Moscow Trump Tower, but they were unsuccessful, said The Washington Post on Sunday night.

In late 2015 and 2016, Trump was pursuing a plan to open a "massive Trump Tower" in Russia's capital city, said business associates and others familiar with documents currently being reviewed by Trump Foundation lawyers.

Russian-born oligarch -- and purported high-ranking figure in Russia's criminal underworld -- Felix Sater strongly encouraged Trump to visit Moscow to help push the proposal with local investors.

Sater -- who recently confided to friends and family that he believes that he and Trump will both end up behind bars -- promised Trump that he could get Russian President Vladimir Putin to say "great things" about Trump in support of the development project.

Sater made grandiose predictions in a November 2015 email to Trump, saying that both he and the Trump organization would soon be having great reason to celebrate "both one of the biggest residential projects in real estate history and Donald Trump’s election as president, according to two of the people with knowledge of the exchange," wrote the Post's Carol D. Leonnig, Tom Hamburger and Rosalind S. Helderman.

Trump never made the trip to Moscow and although he, Sater and investors signed a letter of intent, the project never broke ground.

"Nevertheless," the Post said, "the details of the deal, which have not previously been disclosed, provide evidence that Trump’s business was actively pursuing significant commercial interests in Russia at the same time he was campaigning to be president -- and in a position to determine U.S.-Russia relations."

Discussions about the development deal had trailed off by the time Trump's connections to Russia became a campaign issue, but the new emails point to the likelihood that Trump has concealed other contacts and business inquiries from federal investigators and watchdog groups.