WASHINGTON (BLOOMBERG) - President Donald Trump will delay a second summit with Russian leader Vladimir Putin until next year, the White House announced on Wednesday (July 25).

National Security Adviser John Bolton cited Special Counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election in a statement announcing the delay.

The White House last week said Trump had invited Putin to Washington for a meeting in the fall, a move that was criticised by both Republicans and Democrats in Congress.

"The President believes that the next bilateral meeting with President Putin should take place after the Russia witch hunt is over, so we've agreed that it will be after the first of the year," Bolton said.

Trump has frequently referred to Mueller's investigation into Russian meddling and whether anyone close to Trump colluded in it as a "witch hunt" and blamed the probe for hurting relations between the two countries.

Days before Trump's meeting with Putin this month, Mueller obtained indictments of 12 Russian intelligence officers for their interference in the election.

A Russian gun-rights advocate was separately charged with acting as an unregistered agent seeking to infiltrate political organisations.

NO MUELLER DEADLINE

There's no deadline for Mueller's investigation to end, and he has given no indication he will wrap it up by the end of the year.

For months, Trump's legal team has been trying to pressure Mueller into concluding his investigation, which has gone on for more than a year.

Delaying the Putin visit until "after the first of the year" signals another attempt by the White House to set an artificial deadline.

Trump's lawyers continue to negotiate on terms of an interview with Mueller and have offered to make the president available solely to answer questions about whether his campaign colluded with Russia.

During his first summit with Putin earlier this month, Trump provoked an uproar at home with comments that cast doubt on US intelligence findings that Russia interfered in the 2016 election to hurt Democrat Hillary Clinton and help Trump win.

The president was hit with further criticism after his return to Washington with the announcement that he had invited Putin to visit the White House.

Pushing the meeting until next year would help avoid an uproar that could damage Republican candidates in the November elections.

Trump and Putin may have a chance to meet before then at other gatherings of world leaders, including the annual UN General Assembly meeting in New York in September.