Heckled by local residents, Prime Minister Shinzo Abe joined about 5,000 people including the U.S. ambassador in a memorial service marking the 70th anniversary of the Battle of Okinawa, one of the bloodiest conflicts of World War II.

Resentment over the continuing presence of U.S. bases in Okinawa, a chain of islands at the southern tip of the Japanese archipelago, was evident during the ceremony held to remember more than 200,000 people, many of them civilians, who died in the fighting near the war's end.

As Abe approached the podium, voices from the crowd could be heard shouting, "What are you doing here?" and "Go home!"

The main island of Okinawa is home to about half of the 50,000 American troops in Japan. Residents have frequently complained about crime, noise and other issues related to the U.S. bases.

Okinawa's governor, Takeshi Onaga, a strong opponent of a plan to move a U.S. Marine air station to another part of the main island, took the opportunity to reiterate his demand that the base be moved out of Okinawa.

In his remarks, Abe acknowledged Okinawa's sacrifices both as a battlefront and in the decades since.

"We hope to continue to do our best to lighten the burden of the U.S. military bases on the Okinawans," Abe said. But he indicated the government would go ahead with its plan to keep the base in Okinawa.

Those attending the memorial, including U.S. Ambassador Caroline Kennedy, observed a moment of silence at the Peace Memorial Park.

Even today, wartime remains and unexploded bombs are found underground and at construction sites, said Naeko Teruya, a representative of bereaved families.

"Seventy years since the war has ended, we still feel that the war hasn't truly ended," she said. "We continue to find the scars of war in Okinawa today."