Massachusetts voters who have not yet mailed their ballot for a municipal election on Tuesday should deliver it themselves or vote in-person, the state's top elections official said Monday, warning that the remaining window of time is too short to guarantee any more mail-in votes will count.

Secretary of State William Galvin said the U.S. Postal Service informed his office that it needs "three to five days" to deliver ballots to local elections departments. Under state law, mail-in ballots for Tuesday's municipal contests must be delivered by 8 p.m. to count.

"Do not mail it if you have not mailed it," Galvin said in his pre-election news conference. "My concern is, particularly if this ends up as a close election any place, but let's take Boston as an example — some of the polling suggests it could be close for the second nomination. If that's the case, the last thing we want is ballots that were mailed in good faith not counted."

Election 2020 Massachusetts Democrats (copy)

Massachusetts voters who have not yet mailed their ballot for a municipal election on Tuesday should deliver it themselves or vote in-person, Secretary of State William Galvin said on Monday. 

If a voter requested a mail-in ballot but has not already shipped it out, Galvin said they should either take it to a drop-off location or vote in person at their usual polling place. Fifteen cities and towns will host preliminary elections on Tuesday, including three cities — Boston, Somerville and Lynn — with open mayoral seats.

Galvin said he is "optimistic we'll have a decent turnout tomorrow," offering a "best guess" that Boston will see slightly more than 100,000 votes cast. In Boston, Acting Mayor Kim Janey, City Councilors Andrea Campbell, Annissa Essaibi George and Michelle Wu, and former Boston chef of economic development John Barros are running for mayor. The top two vote-getters in that race will advance and face off in the Nov. 2 general election. -