Source: Mueller raises possibility his office may need to speak to Trump Mueller personally attended a meeting last month with Trump's lawyers

 -- Special Counsel Robert Mueller personally attended a meeting last month with President Donald Trump's lawyers to discuss the ongoing Russia investigation during which the special counsel raised the possibility that his office may need to speak to the president, according to a source with direct knowledge of the conversation.

The source told ABC News it was not the first time Mueller informed Trump's legal team of a desire to speak with the president as part of the ongoing investigation.

The news was first reported by the Washington Post.

For some time, the president's legal team has been discussing options for responding to this potential request from the special counsel, including the possibility of providing written responses in the form of a questionnaire.

According to two sources familiar with the matter there has yet to be any formal request for an interview from the special counsel's office, and so far there is no firm time frame in which this could occur.

The meeting last December was not Mueller's first with Trump's legal team — and according to one source with knowledge of the discussions it won't be the last. The source tells ABC Trump's legal team has consistently asked the special counsel if there is anything they can provide order to expedite this investigation, including turning over documents or making more potential witnesses available for interviews.

Just this past weekend the president expressed a willingness to speak with the special counsel, telling reporters in Camp David "when you've done nothing wrong, let's be open and get it over with."

And in response to a question from ABC's Jonathan Karl last June, that President Trump said he would "100 Percent," be willing to testify under oath about his interactions with former FBI Director James Comey. Asked by Karl if he would speak to Mueller, Trump said, " “I’d be glad to tell him exactly what I just told you, Jon.”

Mueller’s office has declined to comment on negotiations.

White House attorney Ty Cobb provided the following statement: "The White House does not comment on communications with the Office of the Special Counsel out of respect for the Office of the Special Counsel and its process."