Russia’s ambassador the the US said Moscow is ready to discuss a possible visit by President Vladimir Putin to Washington after a surprise invitation from US leader Donald Trump.

With confusion still swirling around what the two men discussed behind closed doors in Helsinki earlier this week, ambassador Anatoly Antonov said it is important to “deal with the results” of their first summit before jumping into a new one.

He said he had not seen Mr Trump’s invitation himself, but added: “Russia was always open to such proposals. We are ready for discussions on this subject.”

The Kremlin has the final say, but has not yet responded to the proposal Mr Trump made on Thursday.

News of the invite caught many in Washington off-guard.

“Say that again?” national intelligence director Dan Coats responded, when informed of the invitation during an appearance at the Aspen Security Forum in Colorado.

“OK,” he continued, pausing for a deep breath. “That’s going to be special.”

Donald Trump
Mr Trump’s performance in Helsinki caused some consternation both in the US and abroad (AP)

Mr Antonov gave a few more details of what the two leaders talked about in Helsinki, but insisted that diplomatic discussions should remain discreet in order to be effective.

He also acknowledged that the two men had discussed a possible referendum in eastern Ukraine.

“This issue was discussed,” the ambassador said, adding that Mr Putin made “concrete proposals” to his US conterpart on solutions for the Ukraine conflict.

Mr Trump tweeted that the two men discussed Ukraine but has not mentioned a referendum or revealed specifics of the Ukraine discussions.

The US and Russia have been on opposing sides of the conflict in Ukraine, unleashed after a popular uprising against a pro-Russian president and Russia’s annexation of Crimea in 2014.

Ukraine and European powers are unlikely to support a referendum in the Donbass region, where pro-Russian separatists hold sway.

The Russian ambassador to Washington also denounced “anti-Russian anger” in the United States and reiterated denials of Russian meddling in the 2016 presidential election — interrupting a questioner to declaire: “We didn’t interfere.”

Donald Trump and Vladimir Putin shake hands in Helsinki
Donald Trump and Vladimir Putin shake hands in Helsinki (Pablo Martinez Monsivais/AP)

He also reiterated denials of Russian involvement in the poisoning of former Russian spy Sergei Skripal in the UK.

Mr Antonov called Monday’s summit in Helsinki a “key event” in international politics and laughed off suggestions that the two men made any “secret deals”.

The ambassador gave details of their discussions on arms control, but said the US has been reluctant to back Russia’s proposals so far. He said the summit had made progress on US-Russian co-operation on Syria’s future.

Meanwhile, Mr Antonov also pushed for the release of a gun rights activist accused of being a covert agent in the US, calling her arrest a “farce”.

US federal prosecutors accused Maria Butina this week of being a covert Russian agent and working to infiltrate US political organisations, including the National Rifle Association, before and after Donald Trump’s election as president.

Butina, 29, denies wrongdoing, and the Russian foreign ministry has started an online campaign for her release.