WASHINGTON • Former US presidential candidate Hillary Clinton said she would not rule out challenging the legitimacy of Mr Donald Trump's election victory if it is found that the Russian interference was deeper than currently known.

She told a radio interviewer on Monday that there was no doubt the Russians influenced the election in favour of the Trump campaign. But the former Democratic contender also admitted that there was no obvious way to mount a challenge.

"I don't know if there's any legal constitutional way to do that. I think you can raise questions," she told National Public Radio (NPR) interviewer Terry Gross.

She pointed to Mr Trump's call during the election campaign for Russia to hack her e-mails.

"He knew they were trying to do whatever they could to discredit me with e-mails, so there's obviously a trail there, but I don't know that in our system we have any means of doing that," she said. "There's no doubt they influenced the election: We now know more about how they did that."

Mrs Clinton appeared on NPR to promote her book, What Happened, which details her campaign and election loss.

Two investigations, one by the US Congress and one by a special prosecutor, are under way into alleged ties between the Trump campaign team and Russian officials.

Mrs Clinton claimed that if positions were reversed and she had lost the popular vote but won the Electoral College majority - and had learnt of Russian influence in the campaign - as president, she would have demanded an investigation even if it disadvantaged her.

"I would have set up an independent commission with subpoena power and everything else."

Asked by the NPR interviewer if she would completely rule out questioning the legitimacy of the election if it was learnt that the Russian interference was even deeper than now known, she replied: "No, I wouldn't rule it out."

Mrs Clinton referred to the Kenya Supreme Court's decision to overturn the recent presidential election result, saying the United States had no such provision in law.

And she called for the abolition of the Electoral College that delivered a majority to Mr Trump after he won key battleground states.

"I think that's an anachronism. I've said that since 2000."

Mrs Clinton accused the media of focusing too little on the alleged Russian hacking of the e-mails of her campaign leader John Podesta, claiming the cache was released to take attention away from an audio tape that revealed Mr Trump boasting in 2005 of his sexually aggressive tactics.

"The press fell for it," she told NPR.