The chairman of the Senate Intelligence Committee maintained over the weekend that investigators spent more than two years pursuing a face-to-face interview with Christopher Steele, but remained unsatisfied with written answers to questions regarding the former British agent's controversial dossier about Donald Trump's alleged ties to Russia.

Sen. Richard Burr of North Carolina and other committee members have "sought an in-person interview with Mr. Steele for 25 months," a Republican committee spokesperson told ABC News.

“As we’ve made clear to Mr. Steele and his attorney, there is no substitute for a face-to-face interview when it comes to answering some of the Committee’s most pressing questions," the spokesperson said. "We wouldn’t be satisfied with written responses from any other key witness, and we are not here, either.”

Christopher Steele, the former MI6 agent who set up Orbis Business Intelligence and compiled a dossier on Donald Trump, shown in London in this March 7, 2017 file photo.(Victoria Jones/PA via AP/FILE) Christopher Steele, the former MI6 agent who set up Orbis Business Intelligence and compiled a dossier on Donald Trump, shown in London in this March 7, 2017 file photo.

The committee's push to go beyond Steele's written responses and speak to him in person comes on the heels of an interview Burr conducted with CBS News earlier this month in which the GOP senator said the former British agent had refused to cooperate with the congressional inquiry.

Burr said the committee was still interested in Steele’s feedback, but that several attempts to reach him have been unsuccessful.

"We've made multiple attempts," he said.

But a lawyer for Steele, who spoke to ABC News on the condition that he not be identified, said the committee didn't require any follow-ups after Steele submitted a comprehensive document of written answers in August.

The Atlantic, citing two anonymous sources, first reported Steele's cooperation via written answers last week.

Steele, a co-founder of the firm Orbis Business Intelligence, has maintained a low public profile since he was outed as the author of a series of memos meant to provide his raw intelligence about Trump’s alleged Russia ties to the Washington, D.C.-based Fusion GPS.

President Donald Trump speaks about a state of emergency from the Rose Garden of the White House, Feb. 15, 2019.(Brendan Smialowski/AFP/Getty Images) President Donald Trump speaks about a state of emergency from the Rose Garden of the White House, Feb. 15, 2019.

The company was conducting research for Trump’s political opponents during the 2016 campaign.

For years, Steele had served as an officer for the British Secret Intelligence Service and was the head of its Russia desk. The agency is known informally by its previous name, MI6, and is the British equivalent to the CIA.

Steele has sought to cooperate with the Senate investigation into Russian meddling in the 2016 campaign, his lawyer told ABC News.

“It’s not true that Chris did not engage with the committee,” Steele’s lawyer said. “The committee pronounced itself satisfied with Chris’s engagement ... by way of written answers."

Steele brokered a formal agreement that had been produced in writing, which the committee accepted, his lawyer said. The existence of that agreement, if revealed by a member or employee of the committee, would violate a strict confidentiality agreement, he added.

“The agreement had very explicit confidentiality provisions. They were very explicit and strict provisions,” the lawyer said.

Chairman of the Senate Intelligence Committee Richard Burr (R-NC) and vice-chairman Mark Warner (D-VA) prepare for a hearing about "worldwide threats" on Capitol Hill, Jan. 29, 2019.(Joshua Roberts/Reuters, FILE) Chairman of the Senate Intelligence Committee Richard Burr (R-NC) and vice-chairman Mark Warner (D-VA) prepare for a hearing about "worldwide threats" on Capitol Hill, Jan. 29, 2019.

A Republican committee spokesperson said Burr has done nothing to reveal the content of Steele’s limited responses.

“Chairman Burr’s comments were accurate and preserved the discretion Mr. Steele requested,” the spokesperson said. Burr's comments in the CBS interview did not reference the written answers or their existence.

To date, the committee has interviewed over 200 witnesses and reviewed more than 300,000 pages of documents, held more than a dozen public hearings, and released two interim reports.