Kirk Spitzer

USA TODAY

TOKYO — Tens of thousands of protesters Sunday on Okinawa called for the closure of all U.S. military bases on the strategically important island, following last month's rape and murder of a 20-year-old woman in which a U.S. base worker is the suspect.

It was one of the largest anti-U.S. base protests in Japan in decades and comes amid delicate negotiations over relocating a key American air base on Okinawa and China's increasingly assertive behavior in the Asia-Pacific region.

A crowd estimated by Japan’s Kyodo News service at 65,000 rallied in sweltering conditions at an outdoor sports stadium, holding signs reading, “Marines, Withdraw” and “Our anger has reached the limit.”

Thousands more protested outside Japan’s parliament building in Tokyo, and protests were planned in more than 40 of Japan’s 47 prefectures, according to local news reports.

Okinawa Gov. Takeshi Onaga, a staunch opponent of the U.S. military presence on Okinawa, expressed outrage over the woman's death. He pledged to work toward removal of U.S. forces and revision of an agreement that, under certain circumstances, limits Japanese jurisdiction over U.S. troops and base workers.

"I hereby express my unflagging resolve to push for drastic review of the Japan-U.S. Status of Forces Agreement and withdrawal of Marines (from Okinawa)," Onaga told protesters. Like many of the demonstrators Sunday, Onaga was dressed largely in black.

More than 25,000 U.S. troops — mostly Marines — are based in Okinawa, a linchpin of the U.S. “re-balance” to the Asia-Pacific region. That’s the largest concentration of U.S. forces in Japan, and residents have long complained of noise, crime and congestion associated with the heavy U.S. presence.

Police last month charged Kenneth Franklin Gadson, 32, a former Marine, with stabbing and strangling the 20-year-old office worker.

Police said Gadson, who also goes by his wife’s family name of Shinzato, led them to the body in a wooded area. Gadson’s attorney said he confessed to the killing. Police said he told investigators that he picked the victim at random.

At the time of his arrest, Gadson was working as a civilian contractor at Kadena Air Base, a sprawling U.S facility in Okinawa. The incident followed the March arrest of a U.S. sailor in March on charges of raping a Japanese woman in a hotel in Naha, Okinawa’s capital.

The incidents seem certain to complicate efforts to relocate a Marine air base at Futenma, Okinawa, to a less densely populated part of the island. Onaga and a majority of Okinawa residents want the base moved off the island.

In an interview Saturday with Japan’s Jiji Press, the senior U.S. military commander on Okinawa said he feels “great pain and anger” over the woman's death.

"The message is this: Do not allow this incident to divide and drive a wedge between American and Okinawan communities here," Marine Lt. Gen. Lawrence Nicholson said.

After Gadson’s arrest last month, Nicholson announced a 30-day period of “unity and mourning” for all U.S. service personnel based on Okinawa. That included a tightened curfew and a ban on alcohol consumption off base.

The Navy imposed a Japan-wide ban on alcohol consumption in early June after a sailor based on Okinawa was arrested on drunk driving charges. The sailor reportedly had a blood alcohol level six times Japan’s legal limit at the time of her arrest. The sailor was arrested after crashing into two cars while driving the wrong way on a major highway.

In an unrelated action, the Navy this weekend gathered two powerful aircraft carrier battle groups in the Philippine Sea, east of Okinawa. It was the largest assemblage of U.S. warships in the region in recent years and follows two incidents this month in which Chinese warships sailed into or near Japanese territorial waters, prompting objections from Japan.

The plan to relocate the U.S. bases developed after three U.S. servicemen were convicted in 1995 of kidnapping and raping a 12-year-old Okinawa girl on her way home from school. The incident sparked massive protests and led to negotiations to reduce the U.S. military presence on Okinawa.