Special Counsel Robert Mueller has finally responded to a letter from President Trump's outside attorneys about what the scope and format of a potential interview with the president would be, sources familiar with the investigation told Fox News on Wednesday.

The sources said Mueller has agreed to cut the number of questions for Trump from an initial list of 49 and is willing to have some questions answered in writing – though he wants other questions answered orally.

However, the sources added that Mueller has not agreed to the president's demands to limit his questioning to matters related to allegations of collusion between the Trump campaign and Russia. The special prosecutor still wants to ask the president about obstruction of justice and other topics.

The sources also said talks with the special counsel about a possible interview are continuing, but as one source said: "There is still a long way to go."

While the Trump legal team's current posture is still not to have the president sit for an interview with Mueller, a source familiar with the investigation told Fox News, “never say never.”

Trump attorney Rudy Giuliani, speaking to reporters following an appearance at a Republican congressional campaign event in New Hampshire, said the president's legal team had received "a letter back" from the special counsel's team on Tuesday and "now we're in the process of responding to their proposal."

"I'm not going to give you a lot of hope it's going to happen," Giuliani said of a potential Trump-Mueller sitdown, "but we're still negotiating."

On Wednesday morning, Trump tweeted that Attorney General Jeff Sessions should stop Mueller's "Rigged Witch Hunt right now, before it continues to stain our country any further."

Sessions recused himself from overseeing the Russia investigation last year, handing off that responsibility to Deputy Attorney General Rod Rosenstein.

Trump has asserted previously that Mueller has too many conflicts of interest for him to fairly lead the investigation, citing his ties to fired former FBI Director James Comey as well as what the president called a "very nasty & contentious business relationship" in a tweet earlier this week.

Democratic lawmakers said Wednesday that Trump's Sessions tweet amounted to obstruction of justice. But White House Press Secretary Sarah Sanders said the message represented "the president's opinion" and not an order to the Justice Department.

"If he wanted to obstruct [the investigation], he'd obstruct it, just end it," Giuliani said of Trump in New Hampshire. "Then you'd all battle whether he has the legal right to do that, which I think he does. But he's not going to do that. He's made it clear he wants it to run its course."

Fox News' Whitney Ksiazek, Tara Prindiville, Judson Berger and The Associated Press contributed to this report.