US    -   US President Donald Trump has confirmed he raised the subject of former Vice-President Joe Biden and his son in a July phone call with Ukrainian president Volodymyr Zelensky.

But Trump denied pressuring Ukraine to investigate his potential Democratic rival in next year’s election. His admission about July’s phone call stoked calls for Democrats to launch impeachment proceedings in Congress.

Adam Schiff, a senior Democrat, said such a move “may be the only remedy”.

Mr Schiff, the influential head of the House Intelligence Committee, had previously resisted calls among rank-and-file Democrats that they attempt to remove the president from office.

What’s the background?

Hunter Biden became a director at Ukrainian natural gas company Burisma in 2014 while his father was Barack Obama’s vice-president with a key role in US policy towards Ukraine. Joe Biden is now the frontrunner to be whichever Democratic candidate takes on Mr Trump in the November 2020 presidential election. US Air Force orders review over Trump resort stays

The controversy over whether Mr Trump pushed his Ukrainian counterpart to launch corruption investigations against the Bidens has dominated Washington in recent days.

US media reported last week that an intelligence whistleblower had filed a complaint over Mr Trump’s communications with a foreign leader and a “promise” that was allegedly made. Joe Biden’s son Hunter (left) was a well-paid director at one of Ukraine’s largest energy companies, Burisma

It emerged last week that the Trump administration was blocking the whistleblower complaint from being handed over to Congress, despite the intelligence inspector general judging it to be “urgent”.

Under US law, if a complaint is considered to be of “urgent concern”, and if the inspector general considers the complaint to be “credible”, then the department head is expected to share the information with Congress within seven days.

Trump told reporters on Sunday that the 25 July call with Mr Zelensky was “congratulatory”, but mentioned corruption and “largely the fact that we don’t want our people, like Vice-President Biden and his son, creating to the corruption already in the Ukraine”.

But he insisted he had done “absolutely nothing wrong”. He has previously accused the as-yet-unnamed whistleblower of being “partisan” and said he knew all his phone calls to foreign leaders were listened to by US agencies.

While Trump suggested a transcript could be released, senior Trump administration officials said it would be inappropriate for private conversations between world leaders to be made public.

The Wall Street Journal (WSJ) has quoted sources as saying Mr Trump had urged Mr Zelensky about eight times to work with his lawyer Rudy Giuliani on an investigation into Hunter Biden, but had not offered anything in return. Democrats have said that if Trump asked Mr Zelensky to investigate Mr Biden, it is tantamount to promoting foreign interference in the 2020 election.

The US president is due to meet his Ukrainian counterpart on Wednesday, among several other foreign leaders at the United Nations General Assembly. There has been no transcript of the 25 July call, and no confirmation of the WSJ story that Ukraine’s president was asked eight times to investigate the Bidens.

The comedian-turned-president is acutely aware of the dangers of being sucked into US electoral politics, of being seen to take sides in what could well be a Trump-Biden election campaign this time next year.