WASHINGTON, March 9 (Xinhua) -- Sam Nunberg, a former campaign aide of U.S. President Donald Trump, on Friday appeared at federal court in Washington D. C. though he publicly claimed earlier that he would not comply with the subpoena issued by Special Counsel Robert Mueller's team over Russia investigation.

Nunberg was accompanied by his lawyer, and a court marshal led them into the grand jury area at 9:30 a.m. ET., local media reported.

On Monday, Numberg told multi U.S. media outlets that he planned to defy the federal subpoena from Mueller's team compelling his testimony.

"Let him arrest me," Nunberg told the Washington Post. "Mr. Mueller should understand I am not going in on Friday."

However, he backed down later on the same day, pledging on CNN that he was "going to cooperate with whatever they want."

The Trump campaign fired Nunberg in August 2015 after racist social media posts emerged.

So far in the Mueller probe, prosecutors have made public grand jury indictments against Trump's former campaign chairman Paul Manafort and his deputy Rick Gates and 13 Russians who allegedly used stolen identities to influence the presidential election through social media.