UNITED NATIONS, N. Y., Nov. 23 — The United Nations has been compelled to restrict radically its relief operations in East Pakistan because of the upsurge in military activity in the last 48 hours.

A spokesman announced that the distribution of relief supplies had been halted outside the cities of Dacca and Chittagong.

The United Nations has been concentrating on distributing 200,000 tons of food monthly to outlying areas threatened by famine.

A week ago, the head of the relief operation warned here that attacks from “any quarter” would compel the work to stop.

The virtual cessation of food distribution was ordered after two of the “minibulkers” used were damaged by mines and six trucks were taken over by the Pakistani Army. Two were later returned.