President Donald Trump said a possible pardon for Paul Manafort "is not something on my mind" after his former campaign chair's prison sentence was raised to 7½ years on Wednesday.

"I feel very badly for Paul Manafort," Trump told reporters at the White House. "On a human basis, it is a very sad thing."

When asked about a possible pardon, Trump said: "I haven't even given it a thought as of this moment. It is not something on my mind."

U.S. District Judge Amy Berman Jackson in Washington ordered that Manafort must serve an additional 43 months for illegal lobbying and witness tampering beyond the 47 months he already received last week from a judge in Alexandria, Virginia, for financial crimes.

Just minutes after his federal prison sentence was raised, Manafort was charged by New York state prosecutors with residential mortgage fraud, conspiracy and falsifying business records.

Trump has no pardon powers over state crimes, and the move by Manhattan District Attorney Cyrus Vance Jr. raises the prospect of a third criminal conviction for Trump's one-time campaign manager.