U.S. prosecutors raised the possibility on Wednesday that an expected star witness may not testify against President Donald Trump's former campaign chairman, Paul Manafort, even as the judge tried to rein in their portrayal of Manafort's lavish lifestyle.

Testimony in the second day of Manafort's trial, the first stemming from special counsel Robert Mueller's 14-month investigation of Russia's role in the 2016 U.S. election, was overshadowed by Trump's call for an end to the probe. Some Democrats accused Trump of obstruction of justice.

Manafort's consulting work for pro-Russian politicians in Ukraine that earned him $60 million also took the spotlight in testimony in federal court in Alexandria, Virginia, outside Washington. Prosecutors questioned veteran political consultant Daniel Rabin about the work he did for Manafort.