The head of the U.S. Postal Service expressed frustration Thursday with ongoing criticism by election officials of how it handles mail ballots while also seeking to reassure voters that it's ready to handle an expected crush of those ballots this fall.

Postmaster General Louis DeJoy pledged Thursday that the US Postal Service will undertake “heroic efforts” to deliver all mail-in ballots on time this year and urged people to put their ballots in the mail at least one week before Election Day on November 5.