US-headquartered news agency Associated Press has asked the country’s government why it has been tracking journalists.

Newly-appointed executive editor Julie Pace has asked the Department of Homeland Security about its use of sensitive government databases for tracking international terrorists to investigate as many as 20 American journalists, including an acclaimed AP reporter.

In a letter to DHS secretary Alejandro Mayorkas, Pace urged the agency to explain why the name of Pulitzer Prize-winning investigative reporter Martha Mendoza was run through the databases and identified as a potential confidential informant during the Trump administration, as detailed in a report by Homeland Security’s inspector general.

“This is a flagrant example of a federal agency using its power to examine the contacts of journalists,” she wrote. “While the actions detailed in the inspector general’s report occurred under a previous administration, the practices were described as routine.”

The investigation – as well as of congressional staff and “perhaps members of Congress” –was reported by Yahoo News and AP on Saturday.

Pace says it represents the latest apparent example of an agency created in the wake of the 9/11 attacks using its vast capabilities to target American citizens.

AP said the latest revelation prompted senator Ron Wyden to call on DHS to immediately turn over the inspector general report to Congress. “If multiple government agencies were aware of this conduct and took no action to stop it, there needs to be serious consequences for every official involved, and DHS and the Justice Department must explain what actions they are taking to prevent this unacceptable conduct in the future,” said Wyden.

AP quoted DHS spokeswoman Marsha Espinosa that Mayorkas was “deeply committed to ensuring the protection of First Amendment rights” and has developed policies that “reflect this priority,” though she did not provide details.

“We do not condone the investigation of reporters in response to the exercise of First Amendment rights,” she said.

In the AP’s letter, Pace called for “assurances that these improper practices and apparent abuse of power will not continue going forward.”

Thirty-nine-year-old Pace (pictured), a longtime Washington journalist, was appointed AP’s executive editor and senior vice president in September. The agency says she “rose to the newsroom’s top leadership spot with a promise to accelerate the AP’s digital transformation”.