WASHINGTON – A federal judge sentenced George Papadopoulos, a onetime aide to President Donald Trump’s campaign, to two weeks in prison and a $9,500 fine on Friday for lying to federal agents about conversations in which he was told that the Russian government had obtained “dirt” on Hillary Clinton.

"I made a terrible mistake for which I paid dearly and I am terribly ashamed," Papadopoulos said at his sentencing hearing. "My entire life has been turned upside down."

Papadopoulos is the first former Trump aide to be sentenced in special counsel Robert Mueller’s investigation of Moscow's interference in the 2016 election. Three others have either pleaded guilty or been convicted.

Papadopoulos admitted last year that he lied to the FBI about interactions in which people he thought were linked to the Russian government described Moscow having “thousands of emails” with damaging information about Clinton. The exchanges came shortly after he joined Trump's campaign and months before U.S. authorities learned that Russian intelligence officers had stolen troves of emails from Democratic political organizations. When they came to light, they triggered the investigation that has loomed over the first two years of Trump’s presidency.

Papadopoulos' lawyer Thomas Breen had asked for leniency for his client. He emphasized that Papadopoulos' lies to investigators came a week after Trump's inauguration, at a time when the onetime policy aide was seeking a senior role in the administration and the president had begun dismissing the Russia investigation as a lie.

"The president of the United States, the commander in chief, had told the world that this was fake news and a witch hunt," Breen said. "The president of the United States hindered this investigation more than George Papadopoulos ever could."

Prosecutors had told Judge Randolph Moss that Papadopoulos should spend up to six months in prison.

His crime, they said in a court filing last month, “was serious and caused damage to the government’s investigation into Russian interference in the 2016 presidential election.”

Moss said he had been considering a 30-day prison sentence but said at Friday's hearing that Papadopoulos had shown "genuine remorse."

Instead, he sentenced Papadopoulos to spend 14 days in prison and another year under the supervision of a probation officer, and required him to perform 200 hours of community service. Papadopoulos' lie, Moss said, was "a serious offense" and "a calculated exercise of self interest over the national interest."

The charges centered on an interview in January 2017 in which FBI agents asked Papadopoulos about his conversations with Joseph Misfud, a professor he believed had connections to Moscow. Papadopoulos told the agents, falsely, that his conversations with Misfud happened before he joined Trump’s campaign in March 2016 and that he did not think they were important. Prosecutors said in a court filing that Papadopoulos’ “lies negatively affected the FBI’s Russia investigation, and prevented the FBI from effectively identifying and confronting witnesses in a timely fashion.”

Partly as a result, they said, agents were unable to “effectively question” Misfud when he visited the United States two weeks later. “The defendant’s lies undermined investigators’ ability to challenge the Professor or potentially detain or arrest him while he was still in the United States,” they wrote.

Papadopoulos’ lawyers had urged Moss to sentence him to probation. In a court filing last month, they described Papadopoulos as “ashamed and remorseful” but said he never derailed the Russia investigation. Instead, they said, Papadopoulos “misled investigators to save his professional aspirations and preserve a perhaps misguided loyalty to his master.”

Breen said Friday that Papadopoulos lied because he was still giddy from his rapid ascent in Trump's campaign, his hopes of securing a job in the new administration and a sense of loyalty to the president. "The message is for all of us to check our own loyalty, to tell the truth, to help the good guys."

Minutes later, Trump seemed to claim vindication. "4 days for $28 MILLION - $2 MILLION a day," he wrote on Twitter, an apparent, if inflated, estimation of the Russia investigation's cost. "No Collusion. A great day for America!"

Papadopoulos has been a central figure in the Russia investigation since it began. The FBI launched its investigation of possible links between Russia and the Trump campaign after learning that Papadopoulos had boasted to an Australian diplomat that the Russian government had political dirt on Clinton more than a month before Moscow’s hacking efforts were known publicly.

For a time, Papadopoulos also looked to be a key informant. A federal court kept his July 2017 arrest secret for more than two months after Mueller’s office argued that making it public would “significantly undermine his ability to serve as a proactive cooperator.”

But in a court filing last month, prosecutors said Papadopoulos ultimately did little to aid their work. Instead, prosecutor Andrew Goldstein said he made "at best grudging efforts to cooperate, and we don't think they were substantial or significant in any regard."

Two other Trump aides – former deputy campaign chairman Rick Gates and former national security adviser Mike Flynn – also pleaded guilty and agreed to cooperate with Mueller’s investigation but haven’t been sentenced. Another, former campaign chairman Paul Manafort, was found guilty of tax and bank fraud charges last month and is awaiting another trial in Washington.

Moss said Papadopoulos will remain free until the federal Bureau of Prisons decides when and where he should surrender. After the hearing, he rode the elevator to the first floor of the federal courthouse, put on a pair of dark sunglasses and strode past a clutch of reporters shouting questions.