Nancy Pelosi has hinted at Donald Trump's impeachment, issuing a statement Sunday to say there will be 'whole new stage of investigation' if the president blocks the whistleblower report from reaching Congress.

The Speaker of the House wrote the Administration 'will be entering a grave new chapter of lawlessness' if it 'persists in blocking this whistleblower from disclosing to Congress a serious possible breach of constitutional duties by the President'.

She added the move would 'take us into a whole new stage of investigation'.

In the latest controversy, Democrats accuse Trump of asking Ukrainian President Volodymyr Zelenskiy for dirt on Joe Biden, related to an investigation into a Ukrainian company that Biden's son served on the board of while his father was vice president.

Pelosi adds: 'The Intelligence Community Inspector General, who was appointed by President Trump, has determined that the complaint is both of 'urgent concern and credible,' and its disclosure 'relates to one of the most significant and important of the Director of National Intelligence's responsibilities to the American people'.'

'The Administration is endangering our national security and having a chilling effect on any future whistleblower who sees wrongdoing.

'We must be sure that the President and his Administration are always conducting our national security and foreign policy in the best interest of the American people, not the President's personal or political interest.'

House Speaker Nancy Pelosi said the Administration 'will be entering a grave new chapter of lawlessness' if it 'persists in blocking this whistleblower from disclosing to Congress a serious possible breach of constitutional duties by the President'

The whistleblower claimed Donald Trump repeatedly pressured the Ukraine president to investigate Joe Biden and his son Hunter for corruption during a phone call

Trump said Sunday that he mentioned Joe Biden when discussing corruption with the new Ukrainian President Volodymyr Zelensky.

While speaking to reporters outside the White House Sunday morning, the president said he and Zelensky agree that they don't want U.S. citizens, including the former vice president and his son, Hunter Biden, creating more corruption in Ukraine.

'We had a great conversation. The conversation I had was largely congratulatory, was largely corruption – all of the corruption taking place. Was 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,' Trump said before departing for a trip to Houston, Texas.

Although Trump admitted to mentioning Biden when speaking about keeping the Eastern European country clear of corruption, he did not address reports that he insisted Zelensky, who took office in May, prosecute Hunter Biden.

He also told reporters after his briefing with the Coast Guard in Texas Sunday that he had every right to bring up Biden and his son's business dealings in the Ukraine during his call this summer.

'I don't even want to mention it but certainly I'd have the right to,' Trump said when asked if he brought up Biden in the call. 'We don't want a country to whom we've been Giving massive aid to corrupt our system. We don't want anything to do with any of that coming to the country.'

But Democrat Rep. Alexandria Ocasio-Cortez called her own party's failure to impeach President Donald Trump a 'national scandal.'

The freshman Congresswoman from New York made the remarks in a tweet late on Saturday, ratcheting up pressure on Pelosi to allow impeachment to move forward.

'At this point, the bigger national scandal isn't the president's lawbreaking behavior - it is the Democratic Party's refusal to impeach him for it,' she wrote.

Ocasio-Cortez's forceful remarks join the growing clamor from some Democrats demanding that party leaders impeach the president, with the intelligence community whistleblower controversy fueling fresh outrage.

Democrat Rep. Alexandria Ocasio-Cortez has called her own party's failure to impeach President Donald Trump a 'national scandal' bigger than 'the president's lawbreaking behavior'

News reports came out Friday suggesting the president applied pressure to Zelensky, demanding he aggressively prosecute Hunter on corruption charges and use military aid as leverage.

Trump had dismissed the story as 'ridiculous' and insists it's being driven by a 'partisan' accuser.

Ukrainian Foreign Minister Vadym Prystaiko defended the president on Saturday and denied reports that Trump had tried to pressure Zelensky during their phone call in July.

'I know what the conversation was about and I think there was no pressure,' Prystaiko said during an interview with local media outlet Hromadske. 'This conversation was long, friendly, and it touched on many questions, sometimes requiring serious answers.'

The alleged whistle-blower wasn't in on the call, and an official briefed on the situation told CNN that the individual doesn't have any direct knowledge of the communications between Trump and Zelensky.

The allegations about Trump emerged in a whistleblower complaint from a member of the U.S. intelligence community, who either heard the call with Zelenskiy or read a transcript from it, though details of the complaint have not been made public.

Trump calls the allegations 'just another political hack job.'

'I have conversations with many leaders. It's always appropriate,' he said of the July 25 phone call with Zelenskiy that is at the heart of the controversy.

Pelosi had earlier said if reports about the complaint bear out, Trump faces 'serious repercussions' and the nation will have 'grave, urgent concerns for our national security.'

But she has long resisted calls from within her party to impeach Trump, likely knowing that Republican-controlled Senate would never convict, and fearing the spectacle would damage Democrats' chances in the 2020 election.

A senior Democratic member of the House Judiciary Committee, which is considering whether to impeach Trump, said the incident could feed into the panel's deliberations.

'This is deadly serious,' Representative David Cicilline said on Twitter. 'If the President does not allow the whistleblower complaint against him to be turned over to Congress, we will add it to the Articles of Impeachment.'

Democratic contenders for the party's presidential nomination are also increasingly joining the swarm calling for impeachment.

'What is Congress waiting for? This is crazy. Unless we take action now, we will see the end of American democracy,' said Beto O'Rourke in a tweet on Saturday.

Biden was more restrained, saying on Saturday that Trump 'could be impeached' depending on the results of a House investigation.

Congress has demanded America's top spy chief hand over the complaint from the whistle-blower, but Director of National Intelligence Joseph Maguire has refused, citing advice not to do so from the Justice Department and White House.

Mike Pompeo, the secretary of state, rejected calls to release a transcript of the phone call, claiming it wouldn't be appropriate.

'Those are private conversations between world leaders and it wouldn't be appropriate to do so except in the most extreme circumstances,' he told ABC News on Sunday morning.

Biden asserted Saturday that he has 'never spoken to my son about his overseas business dealings.'

'Here's what I know,' the top Democrat running for the presidential nomination in 2020 said, 'Trump should be investigated.'

Trump told reporters Sunday that his top political rival is a 'liar.'

When speaking to The New Yorker a few months ago, Hunter recalled a discussion he had with Biden about Burisma, the Ukrainian natural gas provider.

'Dad said, 'I hope you know what you are doing,' Hunter said at the time. 'And I said, 'I do.'