Meanwhile, sacked Federal Bureau of Investigation director James Comey has told the Senate intelligence committee he would not be constrained in discussing his conversations with President Donald Trump.
Comey's testimony is expected to address the circumstances around his firing and his alleged conversations with Trump about the investigation.
White House officials had weighed trying to block Comey by arguing that his discussions with the president pertained to national security and that there was an expectation of privacy.
Family of Oregon stabbing suspect offers condolences
Mangum told news station KPTV that she and her 17-year-old friend were riding the train when Christian started yelling at them. Fletcher said that he is deeply grateful for the support he and the families of the two other men have received.
Burr though has said he has not yet spoken to Mueller about Comey's expected testimony.
"The president's power to exert executive privilege is very well-established", Sanders said.
"I know the Senate Judiciary Committee has made a similar request of Mr. Comey and I support their request", Schumer said in remarks as the Senate reopened on Monday after a weeklong recess.
Former FBI director James Comey is scheduled to testify on Capitol Hill later this week. But if Trump had exerted the privilege in Comey's case, it would nearly certainly have left the impression that the administration was seeking to hide information about the Russian Federation investigation. A spokesman said the presidential powers known as executive privilege will not be employed.
Timeline: How the Trump-Khan relationship grew so heated
Prime Minister May, the Conservative Party leader, was asked earlier on Monday about Trump's criticism of Khan. Trump mocked Khan's comment on Sunday, suggesting in a tweet that the mayor was downplaying the attacks.
"James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press", he tweeted in May. In another moment, the associates said Trump asked Comey to drop an investigation of Trump's first national security adviser, Michael Flynn, about his talks with Russian officials.
"They've talked, but I understand that special counsel has not fenced him off on any way shape or form from the items he intends to talk about", Burr told CNN when asked if Mueller had prohibited Comey from discussing the Russian Federation probe.
President Donald Trump signs a decision memo and a letter to members of Congress outlining the principles of his plan to privatize the nation's air traffic control system in the East Room at the White House, Monday, June 5, 2017, in Washington. But Trump himself has repeatedly said that the Russian Federation probe was on his mind when he removed Comey.
UK police release people arrested after London attack without charge
Canadian Chrissy Archibald was the first victim to be named. "We grieve the loss of our attractive , loving daughter and sister". His footage aired on Sky News shows police searching the market frantically and screaming at people to run for their lives .