WASHINGTON >> Democrats who reviewed a secret whistleblower complaint involving President Donald Trump today called it “deeply disturbing” and said it gives them new leads to pursue as they consider impeachment.

The complaint from an intelligence committee whistleblower, the document at the center of a firestorm about Trump’s handling of Ukraine, was made available to members of House and Senate intelligence committees today after weeks of delay.

Lawmakers were allowed to see the complaint the evening before acting Director of National Intelligence Joseph Maguire was set to testify to Congress about it.

The complaint is at least in part related to a July phone call between Trump and Ukrainian President Volodymyr Zelenskiy in which Trump prodded Zelenskiy to investigate Democratic political rival Joe Biden. The White House released a rough transcript of that call this morning.

House Democrats emerging from a secure room would not divulge details of the complaint, but described it as disturbing and urgent. House Intelligence Committee Chairman Adam Schiff, D-Calif., said it “exposed serious wrongdoing” and “certainly provides information for the committee to follow up with others.”

California Rep. Eric Swalwell told CNN that the whistleblower “laid out a lot of other documents and witnesses who were subjects in this matter.”

The lawmakers did not learn the identity of the whistleblower, according to one person familiar with the complaint who was granted anonymity to discuss it.

A Democratic member of the panel, Illinois Rep. Raja Krishnamoorthi, said the whistleblower “lays out the situation very logically” and “is both acknowledging the things that he or she knows and doesn’t know, which is a hallmark of a credible document.”

House Speaker Nancy Pelosi fully endorsed an impeachment inquiry on Tuesday in light of the Ukraine revelations . Pelosi and Senate Democratic Leader Chuck Schumer also viewed the complaint. Schumer said he is even “more worried” now than he was before reading it and “there are huge numbers of facts crying out for investigation.”

Most Republicans were quiet or defended the president as they left the secure rooms. But at least one Republican said he was concerned by what he had read.

“Republicans ought not to be rushing to circle the wagons and say there’s no ‘there there’ when there’s obviously a lot that’s very troubling there,” said Nebraska Sen. Ben Sasse, a GOP member of the Senate intelligence panel who has been an occasional critic of Trump. He added that “Democrats ought not be using words like ‘impeach’ before they knew anything about the actual substance.”

Trump, whose administration had earlier balked at turning over the complaint, said this afternoon that “I fully support transparency on the so-called whistleblower information” and that he had communicated that position to House Minority Leader Rep. Kevin McCarthy, R-Calif.

The rough transcript released by the White House today showed that Trump prodded Zelenskiy to work with the U.S. attorney general and Trump’s personal lawyer Rudy Giuliani to investigate Democratic political rival Joe Biden.

Lawmakers said they needed to see the complaint, not just the memo about the call, as they investigate the president and whether his actions were inappropriate. Pelosi on Tuesday said that if Trump abused his presidential powers, it would mark a “betrayal of his oath of office.”

It is unclear if the complaint will eventually be made public. Both Republicans and Democrats have called for it to be released.

New York Rep. Elise Stefanik, a GOP member of the House panel, tweeted that “it should be immediately declassified and made public for the American people to read.” New York Rep. Hakeem Jeffries, a member of Democratic leadership, agreed, saying he expects it will be made public “sooner rather than later.”

The House and Senate committees have also invited the whistleblower to testify, but it is uncertain whether the person will appear and whether his or her identity could be adequately protected without Maguire’s blessing. Schiff said this morning that Maguire still had not provided any instructions on how that could happen.

The unidentified whistleblower submitted a complaint to Michael Atkinson, the U.S. government’s intelligence inspector general, in August. Maguire then blocked release of the complaint to Congress, citing issues of presidential privilege and saying the complaint did not deal with an “urgent concern.” Atkinson disagreed, but said his hands were tied.

Maguire is testifying publicly before the House Intelligence Committee on Thursday and privately before the Senate panel. Atkinson, who met privately with House lawmakers last week, will also talk privately to the Senate committee Thursday.