About 4,000 United Auto Workers in six states went on strike against International Truck and Engine Corp. Tuesday afternoon, Oct. 23, claiming the company has unfair labor practices.

ITE is a unit of Navistar International.

The Dow Jones Newswire quotes a company official as saying the unfair labor practice charge is “totally unfounded.”

The strike comes after the UAW contract expired on Oct. 1, and negotiations failed to produce a new agreement.