Mayor Jim Kenney and the city’s top elections official pleaded for patience and confidence from Philadelphia voters a day before polls open for Tuesday’s presidential election, as they moved to defend the city’s voting process from baseless attacks on its integrity.

Kenney and Lisa Deeley, chair of the Philadelphia City Commissioners, acknowledged that it will take several days to tally mail ballots, but vowed that officials will follow principles of “fairness, integrity, access, and accurate results” as they complete their count.

“As you prepare for tomorrow’s election, remember those four principles,” Kenney and Deeley wrote. “They are not empty words or phrases. They are the core of what we are trying to accomplish.”

The pair took the unusual step of addressing voters as President Donald Trump targets Philadelphia — the largest city in a key battleground state and its biggest source of Democratic votes — with false claims of fraudulent activity, while maligning the validity of ballots that are not counted by election night.

The president has also been raising fears of voter intimidation by encouraging his supporters to go to Philadelphia and scrutinize polling places there, which only official campaign poll watchers certified by the city are permitted to do.

Kenney and Deeley wrote in their message Monday that "any aggressive behavior or voter intimidation at the polls won’t be tolerated — this includes attempts by individuals who are not certified poll watchers to access polling locations and observe voting.”

The pair said that polling stations will be staffed with experienced crews and volunteers and that ample locations were being opened, but told voters they should still expect long lines due to strong turnout.

“Lines will seem even longer because of the need for everyone to stay six feet apart" as a COVID-19 safety precaution, they wrote.

Even after polls close, city residents will still be called on to exercise patience, as officials count a record number of mail votes. The process "will easily take several days” and “may determine the outcome in Philadelphia, and in the commonwealth as a whole,” Kenney and Deeley wrote.

The pair concluded their message with a plea for calm.

“We know all Philadelphians have been through a difficult year, and you know the importance of this election,” they wrote. “If you should encounter frustrating or difficult situations on Election Day, let your inner strength guide you. Stay calm, stay respectful, stay above the fray.”