President Donald Trump repeatedly pushed for Ukrainian President Volodymr Zelensky to investigate former Vice President Joe Biden, and his son, Hunter, according to a transcript of the conversation released by the White House.

On Tuesday, Mr Trump said he only froze military aid to Ukraine because he wanted European countries to contribute funds, too.

"We're putting up the bulk of the money, and I'm asking why is that?" he said, adding: "What I want, and I insist on it, is that Europe has to put up money for Ukraine also."

The Republican president also acknowledged pressuring newly elected Ukrainian President Volodymyr Zelensky during a phone call on 25 July to investigate US Democratic presidential frontrunner Joe Biden.

"That call was perfect, it couldn't have been nicer," said Mr Trump, who is up for election next year. "There was no pressure put on them whatsoever.

"But there was pressure put on with respect to Joe Biden. What Joe Biden did for his son, that's something they should be looking at."

Mr Trump later tweeted he had authorised the release "of the complete, fully declassified transcript of my phone conversation with President Zelensky of Ukraine".

"You will see it was a very friendly and totally appropriate call," he wrote.

Mr Trump and his conservative allies have pointed out that Joe Biden, while US vice-president, threatened in 2016 to withhold aid to Ukraine unless it fired a top prosecutor whose office had been investigating a natural gas company where Hunter Biden was a board member.

Other Western officials had called for the same prosecutor to be removed on the grounds that he was soft on corruption. Ukraine's current prosecutor, Yuriy Lutsenko, told Bloomberg News in May he had no evidence of wrongdoing by Mr Biden or his son.

(SOURCE:CNN)