(Reuters) - A U.S. congressional committee on Monday sought records from Education Secretary Betsy DeVos relating to her use of private email accounts, expanding an investigation into how President Donald Trump’s top aides use unofficial messaging services to conduct government affairs.

U.S. Education Secretary Betsy DeVos participates in an interagency working group to discuss youth programs hosted by U.S. first lady Melania Trump that line up with Melania Trump's Be Best campaign in the State Dining Room at the White House in Washington, U.S., March 18, 2019. REUTERS/Leah Millis

U.S. Representative Elijah Cummings, the Democratic chairman of the House Oversight and Reform Committee, sent a letter to DeVos requesting copies of all messages relating to official government business she sent or received from private email accounts or electronic messaging services.

The letter gave DeVos a July 29 deadline.

“This is nothing more than political grandstanding,” Department of Education press secretary Liz Hill said in a statement, adding that an internal department watchdog “has already done a thorough report on this issue.”

The watchdog said in a May 20 report that DeVos sometimes used personal email accounts for government business and did not always save the messages properly.

The report found no evidence of “active or extensive” use of DeVos’ personal accounts, however.

Trump pilloried his Democratic opponent, Hillary Clinton, in the 2016 presidential campaign for her use of a private email server when she was secretary of state. He continues to refer to her emails in speeches and on Twitter.

Cummings is already scrutinizing Trump’s daughter Ivanka Trump and son-in-law Jared Kushner over their use of personal emails and other unofficial messaging to conduct government affairs.

The White House had not produced any documents in response to Cummings’ requests, he said in a July 1 letter to White House Counsel Pat Cipollone.

Cummings said Kushner’s lawyer, Abbe Lowell, had told lawmakers that Kushner used WhatsApp for official duties and that his wife, Ivanka, continued to use a personal email account for her White House business.

Lowell, in a reply to Cummings, denied telling lawmakers that Kushner had communicated through any app with foreign “leaders” or “officials” but said Kushner had used such apps for communicating with “some people,” who were not specified.

CNN reported last year that Kushner communicated with Saudi Crown Prince Mohammed bin Salman via the Facebook Inc-owned WhatsApp messaging application.

The Republican leaders of the oversight panel had also sought information on use of non-official messaging by White House staff in 2017 and 2018. Democrats took over the panel after winning the House of Representatives in 2018 elections.