By Patricia Zengerle
WASHINGTON (Reuters) - The U.S. House Intelligence Committee voted along party lines on Thursday to adopt a Republican report on the panel's investigation of Russia and the 2016 U.S. election, formally ending a probe marred for months by bitter partisan conflict.
The Republican report found no evidence of collusion between President Donald Trump's campaign and Russian interference. It also disagreed with intelligence agencies' findings that Moscow sought to boost Trump's chances of being elected.
Committee Democrats strongly disputed that finding and said they will continue to investigate and, eventually, release their own dissenting report.
Representative Adam Schiff, the panel's top Democrat, said Republicans had declined every Democratic motion during their business meeting, including requests to subpoena witnesses who refused to answer questions, and hold an open hearing with chief executives from technology companies, including Facebook Inc's Mark Zuckerberg.
"The (Republican) majority was not interested in conducting any further investigation, even when the flaws in what we have done so far have become so apparent in the course of the last week," Schiff told reporters.
There are 13 Republicans and nine Democrats on the House Intelligence panel.
Schiff called the decision to end the investigation "a rather sad chapter in our Committee’s long history."
The committee's Republican chairman, Devin Nunes, said the report was based on more than 70 witness interviews and the collection of more than 300,000 documents.
It "will include minority views if the minority submits them," Nunes said in a statement.
Reports have emerged from whistleblower Christopher Wylie this week that British political consultancy Cambridge Analytica improperly accessed Facebook users' information to build profiles on American voters later used to help elect Trump.
Hidden camera footage on British television showed a company official criticizing the House committee's interview.
Wylie has agreed to talk to committee Democrats.
A summary of report findings concluded Russia conducted cyber attacks on U.S. institutions, using social media to undermine the electoral process. It acknowledged contacts between Trump associates and Russians, including Russian efforts to set up a "back channel" to communicate after Trump's election, but said it had not found evidence of collusion.
Russia denies meddling in the U.S. campaign.
The Republican summary recommended steps to crack down on intelligence agency leaks, and raised questions about charges facing Trump's former national security adviser, Michael Flynn, who pleaded guilty to lying to the FBI.
Several congressional Republicans have been harshly critical of the Department of Justice and Federal Bureau of Investigation.
Also on Thursday, the Republican chairman of the House Judiciary Committee, Representative Bob Goodlatte, subpoenaed the Justice Department for documents related to the investigation of an email server used by Trump's 2016 Democratic opponent, Hillary Clinton, and the recommendation to fire Andrew McCabe, the FBI deputy director let go last week.
A Justice spokesman said the department takes the committee's inquiry seriously and is committed to accommodating its request in a manner consistent with its responsibilities.
The House panel's investigation of how Russia might have sought to influence the 2016 U.S. election, and whether Trump associates colluded with Moscow has been marked by partisan disagreements since it began more than a year ago.
Earlier this year, Republicans and Democrats released dueling memos about the probe. Nunes was recused for months after a late-night visit to the White House raised questions about improper communications with Trump associates.
In contrast, the Senate Intelligence Committee released bipartisan recommendations on how to improve election security this week and is continuing its investigation, as is Department of Justice Special Counsel Robert Mueller.
The probes have shadowed Trump's presidency, and the president has repeatedly denounced them, and Mueller, leading to concerns he might fire the special counsel.
(Reporting by Patricia Zengerle; editing by Tom Brown and James Dalgleish)