Donald Trump and Vladimir Putin discussed what the US president again dismissed as the “Russian hoax” in their first known phone call since the release of the special counsel Robert Mueller’s report on Russia’s extensive meddling during the 2016 election campaign.

In an hourlong “very good talk” on Friday, Russia’s president “sort of smiled” about Mueller’s conclusions, Trump told reporters at the White House.

Putin “said something to the effect that it started off as a mountain and ended up being a mouse”, Trump said.

When a journalist asked Trump if he told Putin “not to meddle in the next election”, the president called the reporter “very rude” and said: “We didn’t discuss that.”

Mueller’s report concluded that Russian interference in the 2016 presidential election was “sweeping and systematic”, and included a description of the extensive efforts Russia took to interfere in the 2016 election, including the 25 Russians indicted for that effort.

Ultimately, Mueller’s investigators did not find a criminal conspiracy between Russia and the Trump campaign, but they found multiple contacts. The report concluded that “the Russian government perceived it would benefit from a Trump presidency and worked to secure that outcome, and that the campaign expected it would benefit electorally from information stolen and released through Russian efforts”.

Trump has focused only on Mueller’s top-line conclusions, hailing the lack of evidence of a conspiracy as a political win. He has repeatedly declined to publicly rebuff Putin for the 2016 operation. After the call, Trump tweeted that he and Putin had discussed the “Russian Hoax”, among other topics.

“As I have always said, long before the Witch Hunt started, getting along with Russia, China, and everyone is a good thing, not a bad thing,” he wrote.

The White House press secretary, Sarah Sanders, later said Trump didn’t tell Putin not to meddle in the 2020 election because he’s made that clear in the past. “He doesn’t need to do that every two seconds,” she said.

The Senate Democratic leader, Chuck Schumer, slammed Trump for failing to press Putin on the report’s “extensive evidence that Russia hacked our elections”, saying: “Trump’s priorities are appalling and undermine democracy.”

During their conversation on Friday, which the White House and Kremlin both said lasted more than an hour, Trump and Putin also discussed a possible three-party arms control pact with China, North Korea’s nuclear weapons program, Ukraine and the crisis in Venezuela, where Moscow is propping up the current government over the US-backed opposition.

Trump told reporters that Putin “is not looking at all to get involved in Venezuela, other than he would like to see something positive happen”.

Putin has in fact dispatched Russian troops to support Nicolás Maduro amid an anti-government uprising led by opposition leader Juan Guaidó. The Trump administration has stood on the opposite side, formally recognizing Guaidó as the interim president of Venezuela and calling on Maduro to go.

Trump said the two leaders were also considering a new nuclear agreement “where we make less and they make less. And maybe even where we get rid of some of the tremendous firepower that we have right now.” He said they had discussed the possibility of including China in the deal and that China would “very much would like to be a part of” it.

A Kremlin readout of the call said the two presidents confirmed their mutual desire “to intensify dialogue in various fields, including on issues of strategic stability”, but gave no details about a possible arms deal.