On Wednesday, Pennsylvania election officials officially ordered a recount for the state’s Republican Senate primary between Dr. Mehmet Oz and David McCormick.

The Hill reports:

Pennsylvania Acting Secretary of State Leigh Chapman officially announced the recall Wednesday afternoon, as tallies show Oz and McCormick separated by 902 votes, or 0.1 percentage points. Under state law, a recount is triggered if two candidates are separated by 0.5 percentage points or fewer.

Counties will be allowed to begin their recount on Friday, but they can start no later than Wednesday, June 1. The recount should be finished by June 7, with results due the day after.

The announcement, which has been expected since last week, comes amid an increasingly tense back-and-forth between McCormick and Oz.

McCormick’s campaign is suing to have counted ballots that were mailed in without a written date on the envelopes, as typically required, but which were received on or before Election Day. Oz is arguing for the ballots to be rejected and is getting back up from the state GOP and the Republican National Committee.