U.S. military transport planes delivered 16 cruise nuclear missiles to an air base in southern Belgium last night, and the weapons are now operational, Belgian Defense Minister Alfred Vreven said today.

The installation of the missiles at the Florennes air base, 45 miles south of Brussels, came one day after the Belgian Cabinet approved their deployment, part of NATO's medium-range missile modernization program.

The Cabinet decision, which followed months of debate within the government over when to begin deployment, allowed Belgium to meet the NATO timetable that called for installation to start this month.

Vreven said in a radio interview that the cruise warheads were flown in from the United States Friday evening aboard a C141 transport aircraft, followed several hours later by the missile bodies carried by a C5 Galaxy. "The cruises are operational," Vreven said.

About 850 U.S. Air Force personnel are stationed at the Florennes base to operate the missile battery, U.S. officials said.

Police increased their patrols around the perimeter of the base, which is used by the Belgian Air Force. Vreven said the section of the base where the missiles are located was put under heavy guard by U.S. military personnel. There were no reports of incidents.

Antimissile groups maintain a storefront office in the village of Florennes and last year mounted a peaceful "human chain" demonstration around the base that drew about 10,000 protesters. But unlike demonstrators against NATO's new medium-range missiles in Britain and West Germany, Belgian antimissile groups have not tried to break into the base or block its entrance.

Belgian protesters have called a rally in Brussels Sunday to protest the installation of the weapons. One group, Lawyers Against Nuclear Arms, criticized the government today for installing the missiles before the parliamentary debate on the issue next week.