Hillary Clinton on Sunday sharply criticized Donald Trump over his ‘absolute allegiance’ to Russian policy aims, saying it raised both ‘national security issues’ and new doubts about his temperament.

Trump, her Republican rival in the race for the White House, responded defiantly, saying that he had ‘no relationship’ with Russian leader Vladimir Putin and had never met nor spoken to him by phone, but that ‘if our country got along with Russia, that would be a great thing.’

He said in an ABC interview that he was not about to disavow it if Putin praised him as a ‘genius’ (some Russian speakers say ‘colourful’ was a better translation of the word).

But perhaps further fanning controversy, Trump added that as president he would at least consider acknowledging Russian sovereignty over Crimea, the Ukrainian territory that Russia annexed in 2014 in the face of international condemnation.

Clinton was responding on ‘Fox News Sunday’ to allegations of Russian involvement in leaks of Democratic Party e-mails that embarrassed her on the eve of the just-ended Democratic national convention.

As that convention was underway, Trump urged Russia to find and release several thousand emails that disappeared from Clinton's private server while she was secretary of state, a call that drew a sharp backlash from Democrats and some Republicans.

Democrats and US cybersecurity experts said it appeared Russia had attempted to influence the American campaign in Trump's favor. The leaked emails published by WikiLeaks revealed the distrust of some key Democratic leaders of Bernie Sanders, Clinton's former rival for the Democratic nod.

As that convention was underway, Trump urged Russia to find and release several thousand emails that disappeared from Clinton's private server while she was secretary of state, a call that drew a sharp backlash from Democrats and some Republicans.

Trump's seeming encouragement of Russian hacking, Clinton told Fox, ‘raises issues about Russian influence in our election.’

‘And for Trump to both encourage that and to praise Putin despite what appears to be a deliberate effort to try to affect the election, I think, raises national security issues.’

When an interviewer noted that Trump had claimed ‘he was being sarcastic,’ Clinton replied: ‘If you take the encouragement that Russians hack into email accounts, if you take his quite excessive praise for Putin, his absolute allegiance to a lot of Russian wish-list foreign policy issues,’ it suggests that ‘he is not temperamentally fit to be president and commander-in-chief.’