Democrats on Sunday denounced President Donald Trump, the Justice Department, and the acting Director of National Intelligence, accusing the Trump Administration of violating federal law by withholding information from a whistleblower inside the U.S. Intelligence Community, as the top Democrat in Congress said this could dramatically escalate the standoff over various investigations of the President. 'If the Administration persists in blocking this whistleblower from disclosing to Congress a serious possible breach of constitutional duties by the President, they will be entering a grave new chapter of lawlessness which will take us into a whole new stage of investigation,' House Speaker Nancy Pelosi said in a letter to fellow Democrats on Sunday. Her letter came as critics of the President said Mr. Trump had used a phone call with the new leader of Ukraine to urge him to investigate the son of former Vice President Joe Biden, Hunter Biden, who did work for a Ukrainian gas company. '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,' Speaker Pelosi added. Democrats said the Justice Department and the Acting Director of National Intelligence - who took over in that position just last month when two other top officials were pushed out - were violating federal law by withholding the whistleblower information, evidently about President Trump and Ukraine. By referring to a 'new stage of investigation' involving the President in her letter to fellow Democrats, Speaker Pelosi immediately raised questions about whether she might change her mind on the idea of impeachment proceedings. 'Republicans, it's time to stop making excuses for Trump,' said Rep. Gregory Meeks (D-NY). 'Enough is enough.' 'No one is above the law, not even President Trump,' said Rep. Diana DeGette (D-CO). 'The DNI needs to refer this complaint to Congress immediately.' 'Trump wants to bury a whistleblower complaint that the Inspector General has deemed urgent,' said Rep. Steve Cohen (D-TN). 'It’s the law,' said Rep. Raja Krishnamoorthi (D-IL). 'It’s. The. Law.' tweeted Rep. Don Beyer (D-VA). At issue is what's known as the 'Intelligence Community Whistleblower Protection Act,' which says if an internal complaint is judged to be urgent by the Inspector General of the Intelligence Community - then it is sent to the Congressional intelligence committees. The Inspector General has ruled exactly that - but the Trump Administration refuses to turn over the information. The law does include a provision that if the Director of National Intelligence refuses to give Congress the material, the whistleblower could do it on his or her own. On Sunday, President Trump told reporters his conversation with the President of Ukraine had been a 'beautiful' one, and did not involve any wrongdoing on his part. 'Well, this whistleblower - or whoever it was - because it sounds like it’s not a whistleblower,' the President told reporters. 'You can’t have that happen to a President of the United States,' he said.