Trump reaction to special counsel measured, says White House White House Counsel Don McGahn delivered the news to the president.

 -- The White House had "absolutely no indication" that the Justice Department was going to appoint a special counsel, Robert Mueller, and got a heads up of just 30 minutes before the news broke Wednesday evening, according to a senior White House official.

The FBI's Russia probe has long been a source of contention in the White House and among officials on the Hill and the chorus to appoint a special prosecutor or convene an independent commission has been growing louder in recent days.

White House Counsel Don McGahn personally delivered the news to Trump after receiving a call from Deputy Attorney General Rod Rosenstein, who appointed Mueller.

Trump's senior aides -- Vice President Mike Pence, Chief of Staff Reince Priebus, Press Secretary Sean Spicer, Counselor to the President Kellyanne Conway, Director of Strategic Communications Hope Hicks and Director of Social Media Dan Scavino -- then entered the Oval Office to coordinate the president's response.

Attorney General Jeff Sessions, who previously recused himself from issues pertaining to the election, was at the White House at the time, but it is unclear if he was in the Oval Office when the news was delivered.

According to the senior official with knowledge of the situation, Trump explained how the administration should respond and told his aides that it was an opportunity to focus on their agenda.

The president told them what he wanted to say in a statement, the aides drafted the statement and the president revised it before it was released.

It read, in part, "As I have stated many times, a thorough investigation will confirm what we already know -- there was no collusion between my campaign and any foreign entity. I look forward to this matter concluding quickly."

The official indicated that, in some ways, the staff feels united by Mueller's appointment.

Trump is still expected to hold a joint press conference with Colombian President Juan Manuel Santos Thursday, but sources say Trump will not answer questions about the special counsel.