Special counsel Robert S. Mueller III after a meeting on Capitol Hill in June 2017. Media organizations are asking a federal court to unseal materials used by his team to obtain search warrants on figures in the Russia investigation. (J. Scott Applewhite/AP)

A coalition of news organizations, including The Washington Post, asked a federal court Tuesday to unseal materials used by special counsel Robert S. Mueller III to obtain search warrants in his investigation of President Trump’s former campaign chairman Paul Manafort and others indicted in the probe of Russian interference in the 2016 election.

The news organizations are seeking to compel disclosure of affidavits, records of seizures and the warrants themselves that Mueller filed in bringing indictments against such figures as Manafort and former national security adviser Michael Flynn.

They said the material, which has been shielded under a court order, could contain newsworthy information about the shape and direction of Mueller’s investigation. It could indicate, for example, details of criminal activity suspected by Mueller and the basis for FBI searches.

The Post filed the joint motion with the New York Times, the Associated Press, CNN and Politico.

The request covers warrant material used in the investigation of former Trump foreign policy adviser George Papadopoulos, Manafort associate Rick Gates and 13 Russian nationals who worked for the Internet Research Agency, a St. Petersburg-based company that allegedly plotted to undermine the 2016 election.

Information used to obtain criminal warrants is typically released to the public after a short holding period, typically a few weeks. But some Mueller documents have remained sealed for several months. Manafort and Gates, for example, were indicted in October.

News organizations have partnered to advocate for the unsealing of documents in other high-profile cases, such as the 2016 Pulse nightclub shootings in Orlando, when more than a dozen news companies successfully sought recordings of 911 calls to police on the night of the shooting.

The media coalition says in its motion that the government’s desire to keep the material under seal to protect an ongoing investigation is superseded by the public’s interest in, and right of access to, the Mueller materials.

Mueller was appointed in May and charged with investigating Russian interference in the 2016 presidential election and whether anyone associated with the Trump campaign coordinated with the Russian effort.

Trump has denied his campaign acted inappropriately — frequently asserting in tweets that there was “no collusion” between his effort and Russia.

So far, Mueller has netted a handful of guilty pleas from people associated with Trump, mostly related to allegations that they lied during FBI interviews. Flynn pleaded guilty to lying to the FBI about his contacts with the Russian ambassador. Papadopoulos also pleaded guilty to lying about Russian contacts. Gates pleaded guilty to conspiracy and lying to the FBI about work he did as a political consultant in Ukraine before joining Trump’s campaign.

Mueller has also indicted Manafort on conspiracy, bank and tax fraud, and other charges related to the work he did with Gates in Ukraine. Manafort pleaded not guilty and is scheduled to go to trial in Virginia in July and on related charges in Washington in September.

Mueller’s investigation has also led to the indictment of the 13 Russians and three Russian companies on charges that they orchestrated a complex scheme to pose as Americans on social media and sow dissension online to help elect Trump.

U.S. District Judge Amy Berman Jackson, who is overseeing Manafort’s criminal case, has called the Mueller probe “one of the most high-profile and complicated investigations” in history and has admonished parties to file fewer pleadings under seal, citing public interest in the case.

“The fact that this case is of significant public interest is not a reason to seal things. It’s a reason to unseal things,” Jackson said at a Feb. 14 hearing over disputed bail terms for Manafort and an attempt by lawyers for Gates, his co-defendant, to withdraw from the case before he entered a plea deal.

But Jackson has also allowed both sides to file documents in private and withhold information about finances, relatives and ongoing investigations.

Jackson at the outset of the case also imposed a gag order to prevent pretrial publicity from biasing potential jurors, which neither side opposed.

“This is a criminal trial, and it’s not a public-relations campaign,” Jackson said after Manafort was indicted. “So I want to make it clear, from this point on, that I expect counsel to do their talking in this courtroom and in their pleadings, and not on the courthouse steps.”

At the motion of prosecutors, Jackson last week unsealed portions of Jan. 16 and Feb. 14 hearings that discussed charges brought against Manafort in late February in Alexandria, Va. However, other portions of transcripts and a Feb. 7 hearing about Gates’s change of attorneys right before his plea deal remain secret, even though he has admitted guilt.

U.S. District Chief Judge Beryl A. Howell granted a media request last week to unseal 11 secret court cases concerning independent counsel Kenneth W. Starr’s investigation of President Bill Clinton in the late 1990s. CNN sought the legal proceedings from 20 years ago, saying they could offer a road map for eventually making public aspects of Mueller’s investigation.

Howell cited the passage of sufficient time and public interest in the documents. She also oversees the grand jury used by Mueller, although individual charged cases are assigned to other district judges by random draw.

Spencer S. Hsu contributed to this report.