The US Justice Department faces criticism for its increasing use of subpoenas in attempts to compel journalists to reveal their sources.

The New York Times has revealed that another journalist is facing a subpoena from the administration of United States President Donald Trump, this time about reporting conducted into a secret military operation in North Korea.

On Saturday, the newspaper — one of the most prominent in the country — identified freelance reporter Matthew Cole as the target of the subpoena.

Last September, Cole collaborated with the Times’s national correspondent, Dave Philipps, on an investigation into a secret 2019 mission that saw US Navy SEALs land on North Korean shores.

Their aim was reportedly to plant an electronic bug to intercept communications. But the mission fell apart, according to Cole and Philipps, when the Navy SEALs encountered a North Korean boat and opened fire on those on board.

The Times reported that agents with the Federal Bureau of Investigation (FBI) arrived at Cole’s residence in New York City to deliver the subpoena in February. When Cole was found to be not at home, the subpoena was then sent to his lawyer.

The newspaper cited anonymous sources familiar with the matter.

Such a legal manoeuvre would be the latest in a string of aggressive court actions the Trump administration has taken in its attempts to crack down on suspected government leaks.

The Times is providing legal defence in the case. A lawyer who has represented the newspaper in recent cases, David A O’Neil, was identified as also defending Cole.

O’Neil told the newspaper that Cole “will defend press freedom and the First Amendment from this administration’s brazen attacks on journalists, and he will honor his commitment to his sources”.

In a statement to the news agency Reuters, Times spokesperson Charlie Stadtlander added that the subpoena was “part of the government’s escalating attacks on journalists”.

“The demand that he disclose his sources is another brazen and illegal attack from the administration designed to deny the public information of vital importance,” Stadtlander said.

It is unclear why the Cole subpoena is coming to light now, months after it was issued.

But the Times’s reporting on the subject follows an incident this month in which the Trump administration subpoenaed several of the newspaper’s journalists after they reported on security concerns with the president’s new Air Force One jet. Those subpoenas were withdrawn last week.

In March, the Wall Street Journal and its reporters also received subpoenas seeking to compel the newspaper to disclose its sources for an article about the Pentagon’s warnings regarding the US-Israeli war against Iran.

The Trump administration launched the war alongside Israel on February 28. So far, 18 US service members have been killed, and hundreds of US injuries have been reported.

Thousands have died in Iran, Lebanon and other parts of the Middle East as the fighting spreads across the region.

Typical Department of Justice procedure mandates that subpoenas be a last option in criminal investigations, particularly when constitutional protections are at stake.

Subpoenas against journalists have typically been rare. The First Amendment of the Constitution offers broad protection to free speech and freedom of the press.

But under the second Trump administration, civil rights advocates warn that such legal manoeuvres are increasing in frequency. They are also facing stiff scrutiny in court.

On Tuesday, Democrats in the US Senate demanded information about the Justice Department’s use of subpoenas against journalists at the Times.

“The Department’s lack of transparency and aggressive action toward journalists – in this circumstance, seemingly directed by President Trump after he was upset by negative reporting – both follow this administration’s clear pattern of pressuring news organisations, including several attempts by DOJ to subpoena or intimidate journalists,” Senators Alex Padilla and Adam Schiff wrote in a statement.

Groups like the Committee to Protect Journalists (CPJ) warned that the subpoenas may have “a chilling effect on the work of journalists across the country”.

The Justice Department, meanwhile, has defended its use of subpoenas as necessary to protect national security secrets.