Ordered that the order is reversed, on the law, with costs, Michael E. Phillips' cross motion is granted, and the matter is remitted to the Supreme Court, Orange County, for further proceedings consistent herewith.
A party seeking to stay arbitration of an uninsured motorist claim bears the initial burden of proving that the alleged offending vehicle was insured (see, Matter of State Farm Mut. Auto. Ins. Co. v Fenelon, 202 A.D.2d 436). Since a threshold question of fact exists as to whether the offending vehicle was unidentified, and thus, whether the offending vehicle was insured, the court should have directed a hearing on this issue and permitted joinder of the two insurance carriers of the alleged offending vehicles (see, Matter of Aetna Cas. Sur. Co. v Arhaniotis, 202 A.D.2d 497). Balletta, J.P., Rosenblatt, Pizzuto, Joy and Altman, JJ., concur.