Report: Trump froze aid money before 'pressuring' Ukraine president

US President Donald Trump ordered his chief of staff to freeze military aid meant for the Ukraine just days before pressuring the country's president into investigate Joe Biden, The Washington Post citing three senior White House officials reported on Monday. 

Trump, currently in New York for the annual UN General Assembly, has dismissed the report as a number of prominent Democrats call for impeachment proceedings to begin over reports he sought to extort Ukraine's leader into investigating his political rival. 

Trump told reporters he was taking the threat of impeachment "not at all seriously," before shifting the conversation to former vice president Biden, accusing the Democratic front-runner of engaging in corruption in Ukraine, without any evidence to support the claim. 

Democratic officials have been ramping up pressure for the administration to release a secret whistleblower complaint that sparked the latest crisis. 

Trump confirmed Sunday that he discussed former vice president Joe Biden and corruption allegations in a phone call with Ukraine's leader.a