WASHINGTON (Reuters) – President Donald Trump’s postmaster general on Monday agreed to testify before Congress next week on cuts in service that lawmakers fear could hamper the Postal Service’s ability to handle a flood of mail-in ballots in November’s election.Louis DeJoy, a large donor and Trump ally who became the new postmaster general in June, agreed to testify next Monday before the Democratic-led House of Representatives Oversight and Reform Committee, which is investigating whether service changes adopted in recent weeks have slowed mail deliveries.

Democrats, who control the House, are also weighing legislation on the issue, with Speaker Nancy Pelosi saying in an MSNBC interview on Monday that she expected some Republicans to support it.“We will have vote by mail. It will be successful. We will not depend on the president to anoint it,” she said.

Democrats have raised concerns that, amid a coronavirus pandemic that is expected to result in about twice as many Americans voting by mail as did so in 2016, cost cuts at the Postal Service could lead to missed or delayed ballots.

They have pointed to reductions in overtime, restrictions on extra mail transportation trips and new mail sorting and delivery policies as changes that threaten to slow mail delivery.

Trump has repeatedly and without evidence claimed that mail balloting is vulnerable to fraud and has warned of a “rigged election.” Voting by mail is nothing new in the United States, and one in four voters cast ballots that way in 2016.

Robert Duncan, who chairs the Postal Service board of governors and is a former chairman of the Republican National Committee, will testify along with DeJoy at the hearing next week, the Postal Service confirmed.

Separately, House Democratic Conference Chairman Hakeem Jeffries and Representative Ted Lieu called on the FBI to open a criminal probe into DeJoy.

“There is evidence that making mail-in balloting more difficult may be one of the motivations for the changes instituted at the Post Office,” Jeffries and Lieu wrote in a Monday letter to FBI Director Christopher Wray.