The U.S. Postal Service hit back at the Boston City Council’s claims that delivery failures were frequently leaving residents without pertinent financial documents and medications and could impact

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.

Several councilors said they have been receiving reports of significant delays in mail delivery, or mail not arriving at all, from residents all across the city for months or years.

The Boston City Council called for an emergency hearing to address U.S. Postal Service failures that it says have caused residents to miss out on “vital” documents and prescriptions and raised mail-in voting concerns ahead of the election.

After state election officials raised concerns the U.S. Postal Service is unprepared for this year’s election, Thursday U.S. Postmaster General Louis DeJoy attempted to ease the public’s worries.