Last month, the White House forcefully denied reports that it tried to bar Yates from testifying before the House panel. FBI Director James Comey and NSA Director Mike Rogers, which the committee mistakenly called the national security advisor, were invited to return for a closed hearing the same day.
Late last month, Intelligence Chairman Devin Nunes abruptly canceled that public hearing, at which Obama administration's Director of National Intelligence James Clapper, CIA Director John Brennan, and acting Attorney General Sally Yates all had agreed to testify publicly on what they knew about Russia's tampering in the 2016 presidential election. Yates was also the person who went to White House Counsel Donald McGahn and told him that routine intelligence surveillance into Russian communications showed that former National Security Adviser Mike Flynn had discussed Obama-era sanctions with Russian Ambassador Sergey Kislyak. At that hearing, Comey confirmed for the first time that the FBI was investigating possible ties between Trump's presidential campaign and Russian Federation as Moscow sought to influence the election. A planned closed hearing with Comey and Rogers also was put off. He also testified that there's no evidence to support the president's allegation that Obama "wiretapped" Trump Tower previous year.
But partisan differences persist: Democrats want to focus on the finding of US intelligence agencies that Russian Federation meddled in the election to help Donald Trump win, while some Republicans agree with Trump that the real issue is whether Obama's administration spied on Trump's campaign and leaked what they found.
"Back on track", tweeted congressman Adam Schiff, the panel's top Democrat, noting he sent the letters along with Conaway.
Nunes was a supporter of Trump's campaign and a member of his transition team.
The Senate Intelligence Committee is conducting a separate, similar investigation.
An attorney for Yates alleged that the Justice Department was guidance on what Yates could say about conversations she had with Trump - conversations the department indicated could be covered by executive privilege, then deferred to the White House, according to published correspondance.
In January, US intelligence chiefs said Russian President Vladimir Putin had masterminded the hacking and disinformation campaign that aimed to damage Trump's rival Hillary Clinton and tip the vote in favor of the real estate magnate.
At this point they are a long way from scheduling interviews or hearings with any principal witnesses from either the Obama or Trump administrations, the official said.