U.S. Democrats stepped up pressure Sunday against a cost-cutting campaign by President Donald Trump's appointed Postal Service chief that they fear will hold up mail-in ballots in November's election, with House Speaker Nancy Pelosi calling lawmakers back and several states considering legal action.

Top Democrats in Congress called on Postmaster General Louis DeJoy and another top postal official to testify this month at a hearing on a wave of cuts that has slowed mail delivery across the country, alarming lawmakers ahead of the Nov. 3 election when up to half of U.S. voters could cast ballots by mail.

Democrats have accused Trump, who is trailing presumptive Democratic nominee Joe Biden in opinion polls, of trying to hamstring the cash-strapped Postal Service to suppress mail-in voting.