With votes still being tallied in multiple states Thursday, the presidential race remained too close to call. Former vice president Joe Biden was leading in electoral votes, but several key states had still not been called.

Thin margins could open up the possibility of recounts. The Trump campaign has already signaled it would request a recount in the critical state of Wisconsin, where Biden was declared winner.

As the results continue trickling in, here’s what we know about the rules for recounts in hotly contested states.

Arizona

In Arizona, state law requires a recount when the margin between the top two candidates is equal to or lesser than one-tenth of 1 percent of the total number of votes cast. Secretary of State Katie Hobbs (D) told ABC News on Thursday morning that she did not anticipate that a recount would be necessary. “Our recount margins are very narrow,” she said. “I don’t think we’re going to get to that territory.”

As of Thursday, Biden led by more than 68,000 of the more than 2,800,000 ballots counted. An estimated 85 percent of votes had been counted.

Georgia

Under Georgia law, a candidate can request a recount if the margin is less than 1 percent of votes cast. That request must be made within two days of results being certified.

Trump on Thursday had an approximately 13,000-vote lead out of more than 4.8 million votes counted. An estimated 97 percent of votes cast had been tallied.

Michigan

State law requires a recount be conducted automatically if the margin between two candidates is 2,000 votes or less. A candidate can also petition for a recount if he or she alleges fraud or a mistake and “would have had a reasonable chance of winning the election.” The petition must be filed within 48 hours of the count’s completion.

News organizations declared Biden the winner Wednesday.

Nevada

In Nevada, the loser of the election may request a recount within three working days of the final canvass of votes, no matter the margin — but they must be willing to put down a deposit to cover the estimated cost of the recount.

If the candidate who requests the recount ends up winning the race after a recount, that deposit would be returned. But if the recount shows that they did indeed lose the race, then they would have to foot the bill.

Biden was leading by around 11,500 of more than 1.1 million votes counted by Thursday. About 89 percent of ballots had been counted.

Pennsylvania

Pennsylvania Secretary of State Kathy Boockvar is required by law to order a recount if the winning margin is 0.5 percent or less. The recount would need to be ordered by 5 p.m. on Nov. 12 and completed by Nov. 24.

A recount can also be triggered in each county if requested by three voters.

Trump was ahead by about 109,000 of more than 6.4 million votes counted as of Thursday. About 92 percent of votes had been counted.

Wisconsin

Under state law, a candidate can request a recount if the margin is less than 1 percent. The request must be made no later than 5 p.m. on the first business day after the state has received final results from the state’s counties.

News organizations called the race for Biden late Wednesday.