WASHINGTON (Reuters) - A U.S. judge has given Fusion GPS, the research firm that hired a former British spy to investigate Donald Trump during the 2016 election campaign, until Thursday to reach an agreement with Congress over a subpoena for the firm’s bank records.

Special Counsel Robert Mueller (R) departs after briefing members of the U.S. Senate on his investigation into potential collusion between Russia and the Trump campaign on Capitol Hill in Washington, U.S., June 21, 2017. REUTERS/Joshua Roberts

Judge Tanya Chutkan of the U.S. District Court for the District of Columbia late on Tuesday temporarily extended the deadline for complying with the subpoena, according to court records seen on Wednesday.

Republicans on the U.S. House of Representatives Intelligence Committee earlier this month subpoenaed an unidentified bank for the last two years of records of the accounts of Fusion GPS.

Congressional investigators and Special Counsel Robert Mueller are pursuing allegations in the dossier assembled by former MI6 officer Christopher Steele of connections between Trump’s presidential campaign and Russia.

It has been widely reported that supporters of Republican Jeb Bush, one of Trump’s opponents for the party’s presidential nomination, initially paid for research that was later picked up by supporters of Democratic presidential candidate Hillary Clinton.

A letter sent on Tuesday to Fusion’s lawyers by Perkins Coie, a law firm which represented both the Democratic National Committee and Clinton’s campaign, confirmed that Perkins Coie had hired Fusion GPS in April 2016 to conduct election related research. A source familiar with the matter said Fusion GPS did not hire Steele until late May 2016.

President Trump, who disputes he and his associates colluded with Moscow officials and has called the investigations a “witch hunt,” raised the issue again on Wednesday.

“The whole Russia thing is what it’s turned out to be. This was the Democrats coming up with an excuse for losing an election,” Trump told reporters as he was leaving for Dallas.

Fusion last week sued the bank and asked the court to issue an injunction ordering the bank not to comply with the subpoena. Lawyers for Fusion argued that the subpoena, signed by House Intelligence Committee chairman Devin Nunes, was “exceedingly broad.”

The lawyers also argued that Nunes issuing the subpoena was “not a legitimate legislative activity” because Nunes had “served on President Donald Trump’s campaign” and had “recused himself” from the panel’s probe into allegations by U.S. intelligence agencies that Russia interfered in the 2016 campaign to help Trump. Russia has repeatedly denied the allegations.

In a court filing on behalf of the committee, lawyers for the House of Representatives asked the judge to reject Fusion’s request to block the subpoena. A footnote said the top two Democrats in the House did not endorse the request.

On Wednesday, Trump also echoed unsubstantiated allegations revived on Tuesday by Republicans that when Clinton was secretary of state she approved a sale of U.S. uranium to Russia in exchange for contributions to her husband’s charity.

“I think the uranium sales to Russia and the way it was done, so underhanded, with tremendous amounts of money being passed, I actually think that’s Watergate modern age,” Trump said.