Donald Trump on Wednesday announced he was calling off a second summit with Vladimir Putin until an investigation into Russian collusion was completed.
The US president was planning to host the Russian leader at the White House in the Autumn, a decision that was met with surprise by his own intelligence officials when it was announced last week.
The two leaders held their first one to one meeting in Helsinki earlier this month, after which Mr Trump was heavily criticised for failing to publicly condemn the Russian president for Kremlin interference in the US election.
The probe, which is being headed up by former FBI director Robert Mueller, is investigating potential links between the Trump campaign and Russian actors.
Last week Mr Mueller’s team charged 13 Russian individuals and companies for attempting to sway the outcome of the 2016 presidential election.
Mr Trump and his allies claim the investigation is motivated by political bias and often refer to it as a "witch hunt".
On Wednesday John Bolton, Mr Trump’s national security adviser, said: "The President believes that the next bilateral meeting with President Putin should take place after the Russia witch hunt is over, so we’ve agreed that it will be after the first of the year”.
It follows suggestions that Mr Putin did not think the time was right to hold a second meeting with Mr Trump.
Yuri Ushakov, a top Kremlin aide, told reporters there are other potential venues for the two world leaders to meet in the near future, such as a meeting with G20 leaders in Argentina set for November.
"After the [Helsinki] summit you know what kind of atmosphere there is around its outcome," Mr Ushakov said.
"I think it would be wise to let the dust settle and then we can discuss all these questions in a business-like way. But not now."
In a further sign of tense relations between Washington and Moscow, the US government on Wednesday said it would not accept Russia’s annexation of the Crimean peninsula from Ukraine.
"In concert with allies, partners, and the international community, the United States rejects Russia’s attempted annexation of Crimea and pledges to maintain this policy until Ukraine’s territorial integrity is restored," Mike Pompeo, the US Secretary of State, said.
Mr Pompeo said the US viewed Russia’s claims of sovereignty over the seized territory as "a contravention of international law."
During an appearance before the US Congress, Mr Pompeo emphasised the measures the US had taken to tackle Russian interference in elections, including the expulsion of 60 spies.
In response to the announcement on Crimea, a spokeswoman for the Russian Foreign Ministry said "we know the worth of such declarations".
Separately, Mr Trump said he was hopeful of working out a deal with the European Union and staving off a full-blown trade war.
Amid suggestions the US president is determined to impose damaging duties on car imports, top European officials warned they would respond by putting tariffs on $20 billion of American goods, including agricultural, high-tech products and machinery.
But as he welcomed Jean-Claude Juncker, the European Commission president, at the White House, Mr Trump said: "Hopefully, we can work something out. We expect something very positive to take place.
"We just want it to be a level playing field for our farmers, for our manufacturers, for everybody. And, we also want a big beneficiary, frankly, to be the European Union."
Mr Trump added: "You could call it retaliation, but we just want reciprocal (trade). With the EU, and others, it has to be reciprocal at minimum."
The president praised Mr Juncker as a "tough and smart man" but he said the US had lost hundreds of billions of dollars to the EU in recent years.
Mr Juncker, who has previously called Mr Trump’s trade policies "stupid," said the US and EU were "close partners and allies, not enemies".
He added: "We represent half of the world’s trade. We have to work together. We have to talk to each other, not at one another, and that’s what we do today. We have to focus on reducing tariffs not increasing them, that’s our job."
Despite the warm words it was notable that there was no customary public handshake between the two men. Hours before the meeting Cecilia Malmstrom, the European trade commissioner, said the EU was preparing its response in the event of car tariffs. She said: "We hope that it doesn’t come to that, and that we can find a solution. If not, the EU Commission is preparing a rather long list of many American goods. It would be around $20 billion."
Mr Trump has repeatedly expressed frustration that the EU imposes a 10 per cent tariff on imported US cars, while the US tariff on European cars is only 2.5 per cent.
According to his own advisers the US president has become increasingly determined in recent days to escalate his trade conflict with the EU.
He wants to impose a blanket 25 per cent tariff on nearly $200 billion of foreign cars, and car parts, entering the US before the end of the year.
Mr Trump has said America is being "ripped off" and vowed to show "no weakness" in negotiations.
However, he faced criticism from Republicans in Congress who accused him of abandoning free trade principles and risking damage to the US economy.
Paul Ryan, the Republican House Speaker, said: "Tariffs are not the right answer. I think tariffs are taxes. There are better tools to get them to play fairly."
Seeking to quell the dissent within his own party Mr Trump wrote on Twitter: "Every time I see a weak politician asking to stop Trade talks or the use of Tariffs to counter unfair Tariffs, I wonder, what can they be thinking?
"When you have people snipping at your heels during a negotiation, it will only take longer to make a deal, and the deal will never be as good as it could have been with unity. Negotiations are going really well, be cool. The end result will be worth it!"
Mr Juncker reportedly planned to put forward two ideas in his meeting with Mr Trump. One involved a "plurilateral” deal, reducing tariffs among all major car exporters including Japan and South Korea. A second proposal involved a limited trade deal between the US and EU to get rid of tariffs on industrial goods including cars.