HUNTLEY – The District 158 teachers union inched closer to a strike Tuesday, formally declaring an impasse in negotiations with the district board.

The two sides primarily have split over compensation since early September, the district said in a news release. Neither side has disclosed specifics in negotiations, which started in summer.

The more than 600 teachers of the Huntley Education Association rejected a tentative deal in early September, and in a vote about a month later gave the union the authority to call a strike. No strike date has been set.