New developments in the Special Counsel's Russia investigation. Robert Mueller has reportedly floated the idea of issuing a subpoena for the US President to appear before a grand jury. It's still unclear if the president will agree to an interview - in a case -- he's called a witch hunt. CGTN's Roee Ruttenberg has more.

Donald Trump started the day Wednesday as he does many days. Tweeting. Around 8am, he writes, there was no collusion with Russia. Trump calls it a hoax. And says questions about possible obstruction of justice are a set-up & trap. This, after the New York Times revealed 49 questions a Trump attorney believed the Special Counsel, Robert Mueller and his team, would like answered by the president. And Mueller reportedly suggested he could subpoena Trump if necessary. Trump's lawyers met with prosecutors in early March. Several of the questions focused on people who were fired by Trump including James Comey, the former FBI director. Comey claims the president directly asked him for his loyalty at least once, and suggested it on other occasions. Namely, in asking him to drop an investigation against Michael Flynn, Trump's short-lived National Security Adviser who reportedly met with Russian officials several times. Trump denies making such requests.

At about 9:30 on Wednesday, Trump tweeted again quoting a former U.S. attorney who says such questions are an intrusion into the Constitutional powers of the president to fire anyone. Meanwhile, another Trump lawyer is on his way out. The White House says Ty Cobb plans to retire at the end of this month.  He'll be replaced by Emmet Flood a veteran Washington attorney who represented Bill Clinton during his impeachment.

ROEE RUTTENBERG WASHINGTON It's unclear if Trump will actually be subpoenaed. And if he is, the White House could fight it all the way to the Supreme Court. Still, analysts suggest the Trump team may be trying to publicly undermine the Special Counsel and his investigation, even before its conclusion. Roee Ruttenberg, CGTN, in Washington.