Politico reports that Cummings sent a letter to the White House's legal counsel saying Kushner's lawyer informed lawmakers that President Trump's son-in-law was conducting official government business through WhatsApp, an encrypted messaging service.
On Thursday, Lowell sent an email to Cummings denying that he ever told the chairman Kushner had ever communicated with foreign officials, and that he had followed the proper protocol for classified information.
The committee said that it learned about the use of private email and WhatsApp from a December 2018 conversation from Kushner's lawyer, Abbe Lowell, who also represents the president's daughter, Ivanka Trump.
According to Cummings's letter, Lowell said during their December meeting that Kushner was in compliance with records preservations rules because he took screen shots of his communications and forwarded them to his official email or to National Security Council officials.
He said the document was related to efforts by McFarland and other White House officials to transfer sensitive USA nuclear technology to Saudi Arabia "in coordination with Tom Barrack, a personal friend of President Trump and the chairman of President Trump's inaugural committee".
The committee also said it obtained documents showing former top White House strategist Steve Bannon and former Deputy National Security Adviser K.T. McFarland had used their personal email accounts for White House business regarding the transfer of nuclear technology to Saudi Arabia.
Senior adviser to the President Jared Kushner used private email and a messaging app to conduct official business, the House oversight committee says.
He also said he told Cummings and then-House Oversight Chairman Trey Gowdy, who was also in the December meeting, that he was not familiar with the details of Kushner's use of the messaging application and referred them to the White House counsel.
"In fact, as you know, the White House has not produced a single piece of paper to the committee in the 116th Congress - in this or any other investigation", Cummings wrote, referring to the current session of Congress, when Democrats took control of the House.
Other government officials, including Vice President Mike Pence (when he was governor of Indiana) have been found to have used private emails for government work.
Lowell also denies that he revealed that Ivanka Trump continues to receive official emails to her private account that she does not forward to her government account, in potential violation of the Presidential Records Act.
Robert Giuffra, a lawyer for McFarland, declined comment.
In his letter to Cipollone, Cummings demanded that the White House produce documents related to their investigation into this matter by April 4.
"President Trump, on multiple occasions, appears to have taken steps to hide details of his communications with President Putin from other administration officials, Congress, and the American people", Schiff, Cummings and Engel wrote in a letter requesting access to records and testimony regarding the president's communication with Putin. "The Committee requests that you confirm by March 28, 2019, whether you intend to comply voluntarily with its request or whether the committee should consider alternative means to obtain the information it needs to conduct its investigation", Cummings wrote.
New Zealand to tighten gun laws in wake of mosque killings
A 4-year-old girl also remains in a critical condition at a hospital in Auckland after being transferred there on Saturday. But on Tuesday, Ardern expressed frustration that the video remained available online, four days after the attack.