WASHINGTON, Aug. 21 (Xinhua) -- Paul Manafort, former campaign chairman of U.S. President Donald Trump, was on Tuesday found guilty on eight out of 18 criminal charges of bank and tax fraud by a jury at the federal court in northern Virginia, according to multiple news reports.

Manafort's conviction is the first secured at trial by Special Counsel Robert Mueller's team. Five of the guilty verdicts were for filing false tax documents, and the other three involved foreign bank account registration and bank fraud.

Judge T.S. Ellis III declared a mistrial in the other 10 charges on which jurors said they could not reach a verdict.

The result came after days of deliberations by six male, six female jurors and weeks of exchanges of evidence and testimony in the trial.

CNN hailed the verdict as "a major if not complete victory" for the ongoing Mueller probe into alleged Russian interference in the 2016 U.S. elections, while Fox News called it "a highly publicized showdown" between the White House and Mueller in the past few weeks.

However, the case didn't specifically address any alleged collusion between Trump associates or officials and the Russian government. Trump has repeatedly attacked the Mueller probe as a "rigged witch hunt."

"I think the whole Manafort trial is very sad," Trump told reporters in the White House on Friday, saying Manafort "happens to be a very good person."

Manafort, 69, was a veteran lobbyist. He joined Trump's campaign team in March 2016 and spent three months as Trump's campaign chairman until mid August of that year.

However, the charges largely stem from Manafort's time working for a pro-Russian leader in Ukraine before the 2016 U.S. elections, though the trial is widely seen as a key test of the strength of Mueller's investigation.

Manafort is also facing a separate trial in Washington D.C. on charges of money laundering and fraud conspiracy, which is scheduled for September.