Navistar International Corp. said it wouldn't build any trucks today or Friday at its Chatham, Ontario plant, where a strike began June 1, after workers were injured in a confrontation with security guards. The truckmaker also will stop efforts those two days to bring in temporary workers at the factory, company spokesman Roy Wiley said. As many as six Canadian Auto Workers (CAW) union members were hurt Monday after a security van ran over and critically injured a striker on Monday. Don Milner remains in serious condition after being airlifted to University Hospital in London, Ontario, with a broken arm, shattered hip and internal injuries, CAW representative Joe McCabe said. The factory was building 39 trucks a day before 646 workers represented by CAW Local 127 walked out. The strike, now into its fourth week, began when the OEM and the CAW were unable to agree on $14 million in wage concessions and other costs cuts at the factory.