YOKOSUKA NAVAL BASE, Japan — No one will be able to leave Yokosuka Naval Base on foot for two hours Sunday afternoon during a protest that organizers say will draw 20,000 people.

The protest is to begin at 1 p.m. in Verny Park, next to the base. Organizers said the event is meant to show opposition to a Navy plan, backed by Japan’s government, to bring a nuclear-powered aircraft carrier to Yokosuka in 2008.

On base, outbound foot traffic will stop from 2 to 4:10 p.m. at both Carney (main) and Womble gates. Valid ID card holders still can enter the base by foot and by car at both gates. Outbound vehicle traffic will be routed to Womble Gate and directed to turn left, away from the protest.