Prime Minister Yasuhiro Nakasone does not normally find it necessary to comment on small town by-elections. But this afternoon he told reporters it was "regrettable" that Kiichiro Tomino had been elected mayor of Zushi city, population 59,000.

Tomino ran a one-issue campaign -- opposition to construction of housing for 920 housing units for U.S. Navy personnel at an abandoned munitions dump that has become an unofficial sanctuary for birds in recent years.

Tomino maintains that his only purpose was to safeguard the peace and green at the 720-acre site, located 25 miles south of Tokyo. Japan's military ties with the United States, which Nakasone has worked to strengthen, are a question for central not local government, he said.

Still, his victory, and the nationwide attention it has generated, shows the mixed feelings many Japanese retain about that relationship, under which 50,000 U.S. troops are stationed in Japan. Central government officials today said they still plan to proceed with the project at the Ikego dump site. It is needed to support the nearby Yokosuka naval base, one of the U.S. Navy's most important facilities in Asia.

Tomino tonight hailed his victory as one for Americans, too. "This is my message to the American people," he said in a telephone interview. "I was born in 1944 and educated in the school system where the Americans taught us about selfgovernment and democracy.

"The campaign has shown me that what we learned from you is alive and well in the local communities of Japan," he said. U.S. forces occupied Japan from 1945 to 1951 and effected broad-ranging changes in government and education.

Some members of the government, however, saw the campaign as a side-door attack on the U.S. presence. As a result, the ruling Liberal Democratic Party sent senior officials to Zushi to campaign for the incumbent mayor, Torayoshi Mishima, who had reluctantly agreed to back the project.

Throughout Japan, U.S. bases have been the targets of citizen campaigns that appear to be partly motivated by anti-Americanism. They have rallied against jet noise around Atsugi air base, for instance, and the deployment of F16 fighters at Misawa air base.

Last month, when 11 U.S. B52 bombers flew to Okinawa's Kadena air base to escape rough weather at their base in Guam, the local prefectural legislature passed a resolution saying even to avoid a typhoon B52s were not welcome.

A decade ago, Japan was known for mercury-polluted waters and cities where traffic police had to breathe pure oxygen once an hour to stay on their feet. Though the government has imposed controls and cleaned up much of the mess, it remains far apart from citizen activists.