Phone-call records disclosed in the House Intelligence Committee’s impeachment inquiry report released Tuesday show extensive contact between President Trump’s personal attorney, Rudolph W. Giuliani, and the White House during key moments of the Ukraine saga.

The call records provide powerful circumstantial evidence that Giuliani was coordinating with the White House on his Ukraine gambit, something Giuliani has previously acknowledged. The records also show contact between a Giuliani associate, Lev Parnas, and one of Trump’s key defenders in Congress, the ranking Republican on the House Intelligence Committee, Rep. Devin Nunes (Calif.).

The willingness of phone companies to turn over the records in response to the congressional request also served as a reminder of the power of Congress’s investigatory tools, despite efforts by Trump to block government officials from complying with the impeachment inquiry.

During a news conference Tuesday, the chairman of the House Intelligence Committee, Adam B. Schiff (D-Calif.), said “the phone records show that there was considerable coordination among the parties, including the White House.”

The report attributes the phone records to “document production” from AT&T and Verizon, suggesting the companies were subpoenaed. The report doesn’t say whose phone records were subpoenaed, but the text suggests the committee obtained extensive records of calls by Giuliani and Parnas.

Giuliani’s phone records include calls with a number designated only as “-1,” sometimes close in time to calls between Giuliani and the White House switchboard. The suggestion is that “-1” might be a phone belonging to Trump, though the report does not state that clearly.

Schiff, speaking to the Los Angeles Times, said he suspects the number could be Trump’s and that the committee is trying to find out whether calls logged as “-1” indeed came from the president.

A lawyer for Giuliani declined to comment.

The records show that Giuliani made several calls to the White House on April 24, the same day that U.S. Ambassador to Ukraine Marie Yovanovitch was summoned to Washington and told that she had lost Trump’s confidence. Giuliani called the White House at least seven times that day between 7:47 a.m. and 8:09 p.m. He also received a call from a White House number and spent more than eight minutes on the line with “-1.”

The records show several calls and text messages in early August between Giuliani and numbers associated with the White House and the Office of Management and Budget. At that time, U.S. diplomats were trying to set up an Oval Office meeting between Trump and Ukrainian President Volodymyr Zelensky that the Ukrainians were eager to schedule. Giuliani’s calls and texts include a nearly 13-minute call with an OMB official and “-1” on Aug. 8.

Mick Mulvaney, director of the Office of Management and Budget, is also simultaneously serving as the acting White House chief of staff.

The report uses the phone records to bolster evidence that Giuliani, his associates and “one or more individuals from the White House” coordinated a smear campaign against former vice president Joe Biden.

In the weeks leading up to Biden’s April 25 announcement that he would seek the presidency, the logs show contacts between Giuliani, Parnas and John Solomon, then a conservative columnist for the Hill newspaper.

On the day that Biden announced his campaign, Solomon published a piece alleging that Ukraine had planted Russia collusion allegations against the Trump campaign. The column also described Biden’s efforts to oust a Ukrainian prosecutor and questioned whether Biden had acted to protect his son Hunter, who served on the board of a Ukrainian energy company facing an investigation, as the fired prosecutor has alleged. No evidence has surfaced backing the prosecutor’s claim.

At 7:14 p.m. that evening, Giuliani received a call from “-1” that lasted nearly five minutes. Moments later, according to the records, Giuliani spoke to Fox News host Sean Hannity for 36 seconds. Later that night, Trump was a guest on Hannity’s show. The Fox News host asked Trump to respond to Solomon’s latest column.

Trump said, “that sounds like big, big stuff. I’m not surprised.”

The call records also show a number of phone calls between Nunes and Giuliani and between Nunes and Parnas earlier this year. Joseph Bondy, a lawyer for Parnas, has accused Nunes and his staff of participating in Giuliani’s efforts to get Ukraine to investigate Biden.

Call records also show that on May 10, as Giuliani came under fire for a planned trip to Ukraine to meet Zelensky, the former New York mayor began trading missed calls with Kash Patel, an official at the White House National Security Council who previously worked for Nunes.

In the afternoon, after the aborted calls, Giuliani and Patel managed to connect and spoke for over 25 minutes, according to the report. Five minutes later, Giuliani connected with “-1” for more than 17 minutes.

Patel has denied news reports — based in part on the closed-door testimony from Fiona Hill, former top Russia adviser on the National Security Council — that he was serving as a back-channel to Trump on Ukraine issues.

“At no time have I ever communicated with the president on any matters involving Ukraine,” Patel said earlier this year in a statement to Axios. “Any reporting to the contrary, and any testimony provided to Congress, is simply false, and any current or former staff who suggest I have raised or discussed Ukraine matters with President Trump, are similarly misinformed or spreading outright falsehoods.”

The report Tuesday doesn’t detail any communications between Patel and Trump regarding Ukraine. It does say that he was talking to Giuliani right at the moment when Ukraine was at the top of the former New York mayor’s agenda.

After his call with Patel and “-1,” Giuliani went on Fox News and said that he would be canceling his trip to Ukraine, because Zelensky was surrounded by “enemies of the president.”

A spokesman for the National Security Council didn’t respond to a request for comment regarding Patel’s call. Nunes, speaking on Tuesday to Hannity on Fox News, said he has known Giuliani for a long time and spoke with him about Robert S. Mueller III’s probe. Nunes said he didn’t really recall the name Parnas but it was possible he had spoken to him and needed to check his phone records. “But it seems very unlikely I’d be taking calls from random people,” Nunes said.

Another Parnas lawyer, Edward B. MacMahon Jr., reiterated that, “with appropriate protections,” his client would fill in the blanks for lawmakers on the content of the calls. “All phone records show you is that a phone call was made,” he said. “It takes a participant in the phone call to tell you what was said.”

It is unlikely Parnas will actually testify. Parnas is seeking immunity from Congress before talking to lawmakers. Such a move could complicate the campaign finance charges against him in federal court in New York, and lawmakers rarely take such a step without the blessing of the Justice Department. He has denied wrongdoing.

John Hudson, Felicia Sonmez and Matt Zapotosky contributed to this report.