TOKYO -- About 5,000 people, including Japan's prime minister and the US ambassador to Japan, held a memorial service Tuesday to mark the 70th anniversary of the Battle of Okinawa, one of the bloodiest conflicts of World War II.

They observed a moment of silence at Peace Memorial Park in Okinawa, a chain of islands at the southern tip of the Japanese archipelago.

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

"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."

Many civilians were among the more than 200,000 people who died in the fighting on Okinawa in the final months of World War II.

Japanese Prime Minister Shinzo Abe and US Ambassador Caroline Kennedy attended the somber ceremony. (AP)