Democrats Abroad Canada is warning Americans that a potential postal workers strike this weekend could affect the ability to vote in next week’s election.

In a news release Wednesday, Democrats Abroad Canada urged American voters living in Canada to take immediate action if they want their ballots to reach the U.S. in time for the general election on Nov. 5 for president.

Jacob Wesoky is the executive vice-chair of Democrats Abroad in Canada. He said votes from abroad have made a significant impact on U.S. elections.

“With approximately 625,000 eligible U.S. voters in Canada, a Canada Post strike could mean that ballots sent by mail may not arrive in time to be counted,” Wesoky said. “It also means that ballots already sent that are still in Canada when the strike begins may be affected.”

On Wednesday, Canada Post presented its latest contract offer to the Canadian Union of Postal Workers. The union announced earlier in the week that its members voted to support a strike by Sunday if a deal could not be reached.

The release from Democrats Abroad Canada said voters may face severe barriers to having their votes counted this election without a reliable mailing option. For mail-in only return states, the release encourages voters to use courier services.

“We want every U.S. voter in Canada to know that there are still ways to ensure their vote reaches the U.S. on time despite this disruption,” Wesoky said.

Democrats Abroad Canada is part of the official Democratic party organization for Americans living outside the United States.

All state voter requirements can be viewed at VoteFromAbroad.org.