WASHINGTON: The US Justice Department has subpoenaed four New York Times journalists following reports about alleged security concerns involving President Donald Trump’s new Air Force One, widening an investigation into possible leaks of sensitive government information.

The journalists have been ordered to appear before a federal grand jury in Manhattan after the newspaper reported on security features of the newly converted presidential aircraft. The Justice Department says the reporters are not the targets of the investigation and that authorities are seeking to identify people who disclosed classified information.

The four journalists named by the Times are Julian E. Barnes, Eric Lipton, Tyler Pager and Eric Schmitt. Some of the subpoenas were delivered by federal agents directly to the reporters at their homes.

The investigation follows New York Times reporting that raised questions about whether the new Air Force One had all high-level security systems fully installed.

Trump used the new aircraft while travelling to a NATO summit in Turkey but returned on an older presidential jet. The Times reported that security concerns had influenced the aircraft switch, while Trump offered a different explanation for the change.

The new presidential aircraft was donated by Qatar and later converted for use as Air Force One. Reports have focused on whether its accelerated conversion left some advanced security capabilities incomplete.

The subpoenas have renewed debate in the United States over national security investigations, government leaks and press freedom.

The New York Times has criticised the move, while media and press freedom groups have raised concerns about forcing journalists to testify over confidential reporting. The Justice Department maintains that its investigation is focused on the source of the alleged leak rather than the journalists.

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