The US Postal Service is warning states that it may not be able to meet deadlines for delivering mail-in ballots before Election Day, according to a report Friday.   

The ballots would complicate an already tricky electoral process in the midst of the coronavirus pandemic.

The postal service recently sent letters to 46 states and the District of Columbia that said election laws established by the states would not guarantee ballots cast by mail for the November election would arrive in time to be counted, according to a report by the Washington Post.

“Certain deadlines concerning mail-in ballots, particularly with respect to new residents who register to vote shortly before Election Day, appear to be incongruous with the Postal Service’s delivery standards,” Thomas Marshall, general counsel for the postal service, wrote in a letter to California Secretary of State Alex Padilla. “This mismatch creates a significant risk that some ballots will not be returned by mail in time to be counted under your laws as we understand them.”

Marshall urged Padilla to keep the postal service´s delivery standards and recommendations in mind to make decisions about voting processes.

He asked secretaries of state to require residents to request ballots at least 15 days before an election, rather than the four days allowed under some state laws.  

News of the letters comes days after US President Donald Trump said mail-in voting is likely to be rife with fraud without providing evidence.

As record numbers of people are expected to vote by mail, some states are thinking of implementing changes to ensure mail-in and absentee ballots would be mailed and received in time to be counted.