FILE PHOTO: Rick Gates, former campaign aide to U.S. President Donald Trump, departs after a bond hearing at U.S. District Court in Washington, U.S., December 11, 2017. REUTERS/Joshua Roberts

(Reuters) - U.S. Special Counsel Robert Mueller on Tuesday asked a federal judge for more time before sentencing former Trump campaign aide Rick Gates because of his ongoing cooperation, suggesting the probe into Russian interference may still have a ways to go.

The latest request for more time before sentencing came in a joint filing by Mueller’s office and Gates’ lawyers to U.S. District Judge Amy Berman Jackson in Washington, who is overseeing the case.

In a request similar to one made to the judge in November, they cited Gates’ cooperation with “several ongoing investigations” in asking for another 60 days before they update the judge again about the case and whether it was time to move to sentencing.

The request to push the Gates’ case into at least mid-March came amid a flurry of recent news reports suggesting that Mueller may be winding down his investigation, with a final report possibly being submitted in the coming weeks.

It was not clear which probes Gates is helping with, but he was deeply involved in running the Trump campaign’s day-to-day operations and played a key role at the Republican National Convention where Donald Trump became the party’s nominee.

Gates, a former business partner of Trump’s former campaign chairman, Paul Manafort, stayed on in the campaign even after Manafort resigned in August 2016 over a controversy about cash payments from Ukraine, and also served on the presidential transition team.

Gates was a star witness over the summer in a high-profile trial of Manafort, after he had pleaded guilty to lying to the FBI and conspiracy against the United States in Mueller’s probe in exchange for agreeing to cooperate with prosecutors under a deal that could lead to a reduced sentence.

Mueller is investigating whether there was collusion between the Trump campaign and Russia. U.S. intelligence agencies have concluded that Moscow interfered in the 2016 presidential election. Russia has denied it meddled. Trump has denied there was any collusion, and has called the special counsel’s investigation a witch hunt.