New York attorney general subpoenaed former President Donald Trump and two of his children, Ivanka and Donald Trump Jr., demanding their testimony in connection with a civil investigation into the family's business practices, a court filing made public Monday said. 

The subpoenas came over Attorney General Letitia James' investigation into the family's business practices, which include "the valuation of properties owned or controlled" by Trump and the Trump Organization.

Her attempt to get a testimony from the former president had been reported in December. However, Monday's court filing became the first public disclosure that investigators were also seeking information from Trump's eldest children.

Seeking to put an end to James' investigation, former President Trump sued her in federal court in December, claiming she had violated his constitutional rights in a "thinly-veiled effort to publicly malign Trump and his associates."

The attorney general's office had gone to court to enforce a subpoena on Trump Jr., and a judge forced him to testify after his lawyers abruptly canceled a previously scheduled deposition. 

Although the civil investigation is separate from the district attorney's criminal investigation, James' office has been involved in both.

Last year, then-District Attorney Cyrus Vance Jr. gained access to the longtime real estate mogul's tax records following a battle that went to the US Supreme Court twice. Vance also brought tax fraud charges against the Trump Organization and its CFO Allen Weisselberg.

Weisselberg pleaded not guilty to charges alleging he and the company evaded taxes on lucrative fringe benefits paid to executives.

The probes into the organization and its associates come over allegations in news reports and by Trump's former personal lawyer asserting that the former president had a history of misrepresenting the value of his assets.

James has also been investigating similar issues relating to a Trump office building in New York City, a hotel in Chicago, Illinois, and a golf course near Los Angeles, California.