WASHINGTON (BLOOMBERG) - President Donald Trump spoke with Russian counterpart Vladimir Putin, amid the intensifying investigation into whether the Kremlin meddled in last year's US election to help Trump win.

The call came Thursday (Dec 14), after Putin used his annual news conference to praise the US financial markets' rise and other "quite serious achievements" under Trump, whom he said he was on first-name terms with. The Russian President also dismissed as "spy-mania" allegations of his collusion with the Trump campaign and suggested the FBI has been drugging the whistle-blower who led to Russia's Olympics ban.

The White House said Trump thanked Putin for "acknowledging America's strong economic performance". The phone conversation came after a request from the US, the Kremlin said in an e-mailed statement.

The two leaders talked about the North Korea's nuclear weapons programme, as well as other bilateral issues, the Kremlin said without elaborating. Neither the White House nor the Kremlin readout of the call made any mention of the meddling issue.

On Dec 1, Trump's former national security adviser, Michael Flynn, pleaded guilty to lying to federal agents about his contacts with Russia. The plea documents made clear that Flynn was cooperating with Special Counsel Robert Mueller's probe into Russian interference in the 2016 presidential election.