President Donald Trump has denied he ever worked for Russia against US interests.
There have been multiple reports in US media in recent days about Mr Trump's relationship with Moscow, an issue that has dogged his presidency from the outset.
The New York Times reported that in 2017 law enforcement officials began investigating whether Mr Trump had been working on behalf of Russia against US interests.
But speaking from the White House South Lawn on Monday, he said: "I never worked for Russia."
The president blasted former FBI and Justice Department officials and repeated his claim that the investigation into his ties to Moscow is a hoax.
After two years in office, the president is still being questioned about whether he was compromised by Russian intelligence agencies.
Special counsel Robert Mueller is looking into Russian election interference and whether Mr Trump's campaign coordinated with the Russians. He is also investigating possible obstruction of justice by Mr Trump.
Monday's denial demonstrated the pressure Mr Trump faces as Mr Mueller's investigation shows possible signs of wrapping up.
The president raised eyebrows over the weekend when he didn't directly answer a question about possible ties to Moscow in an interview with Fox News host Jeanine Pirro.
When Pirro asked if he had ever worked for Russia, Mr Trump said it was "the most insulting thing I've ever been asked".
"I think it's the most insulting article I've ever had written, and if you read the article you'll see that they found absolutely nothing," he said.
Mr Trump went on to assert that no president has taken a harder stance against Russia than he has.