The Japanese prime minister, Shinzo Abe, lays a bouquet of flowers during a memorial service to mark the 70th anniversary of the battle of Okinawa. Photograph: Hiroko Harima/AP
Japan’s prime minister, Shinzo Abe, has been heckled at an event marking the anniversary of the end of the bloodiest battle of the Pacific during the second world war, as criticism mounts over his attempts to allow Japanese troops to fight overseas for the first time in seven decades.
Shouts of “Go home!” and “Warmonger!” could be heard as Abe, a nationalist whose attempts to reinterpret Japan’s pacifist constitution have sent his approval ratings to record lows, arrived at a ceremony on Tuesday to mark the end of the battle of Okinawa in which more than 200,000 civilians and soldiers died.
On a day when 5,000 people, including the US ambassador to Japan, Caroline Kennedy, gathered in the town of Itoman on Okinawa’s southern tip to remember those who died in the 82-day battle, a poll revealed strong public opposition to Abe’s plans to strengthen the role of the country’s military.
Criticism of Abe in Okinawa is running high over his support for the construction of a new US marine corps airbase on a pristine stretch of Okinawa’s coastline to replace an existing base located in the middle of a densely populated city.
Okinawa’s governor, Takeshi Onaga, has vowed to block the plan, which would also involve the relocation of about 8,000 US troops and their families from the island to Guam and other US Pacific territories.
Abe, who appeared shaken by the rare display of public anger, acknowledged Okinawa’s role in maintaining Japan’s security since the end of the second world war.
The island, located about 1,000 miles south of Tokyo, hosts more than half the 47,000 US troops in Japan and three-quarters of US bases, despite accounting for just 0.6% of Japan’s territory.
“People in Okinawa have long been asked to carry a big burden for our security,” Abe said. “We will continue to do our best to reduce it.”
He added: “We must take pride in the path of peace we have single-mindedly walked in the last 70 years and make ceaseless efforts to establish world peace.”
Abe was speaking near the spot where Japanese troops who had been ordered never to surrender forced terrified local people to throw themselves off cliffs rather than risk being captured by the Americans who, they were told, would rape and kill them.
Survivors said that Japanese troops gave civilians two grenades each: the first was to be hurled at the invading enemy, and the second to be detonated in group suicides.
The island is still littered with human remains and unexploded ordnance, said Naeko Teruya, a representative of the 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.”
By the time the fighting ended, about 100,000 Okinawan civilians were dead, as well as 80,000 Japanese troops. At least 12,000 US soldiers also died in a battle that many believed offered a bloody foretaste of what could happen if the US attempted an invasion of the Japanese mainland.
Japan surrendered almost two months later, days after the US dropped atomic bombs on the cities of Hiroshima and Nagasaki.
Onaga received a warmer welcome when he referred to the unfair military burden he and many islanders believe they have shouldered since Okinawa was handed back to Japanese control in 1972.
He urged Abe to reconsider a 20-year-old agreement between Tokyo and Washington to build a new offshore runway on the island, saying his election as governor last year demonstrated the strength of public feeling against the move.
“We strongly demand that the government cancel construction … and review its policies of reducing Okinawa’s base burden once again,” he said.
Okinawa’s strategically important role as a host to US military bases has taken on renewed importance amid anxiety over increasingly assertive Chinese claims to islands in the South and East China Seas.
Some local people fear their island could once again be dragged into war if Abe pushes ahead with plans to reinterpret the US-authored pacifist constitution and allow Japanese troops to engage in collective self-defence – or coming to the aid of an ally under attack.
Article 9 of the constitution prohibits Japan from threatening or using force as a means of settling international disputes. Successive administrations in Tokyo have interpreted that to mean that troops can only go into battle in defence of direct threats to Japanese territory.
Abe’s quest to end that strictly defensive posture recently suffered a setback after three respected scholars said the changes were unconstitutional.
Voters also appear to doubt Abe’s reassurances that the change would not increase the likelihood of Japanese troops becoming embroiled in US-led conflicts.
A poll by the liberal Asahi Shimbun released on Tuesday showed support for the Abe cabinet at 39%, the lowest since he took office in late 2012. The newspaper attributed the slump to growing public opposition to Abe’s security bills. According to the poll, 53% of respondents oppose the new legislation, while 29% support it.
The end of the Okinawan battle was marked as South Korean women who were forced to work as sex slaves for the Japanese army before and during the war said they would file a $20m (£12.7m) lawsuit next month at a US court to seek financial compensation from Tokyo.
Ten surviving “comfort women”, led by 89-year-old Kim Bok-dong, will lodge the suit at a California district court on 1 July, according to their attorney.
“The Japanese government should offer an official and sincere apology for wrongdoings by their ancestors and restore our honour,” Kim told reporters outside the Japanese embassy in Seoul.
Mainstream historians say up to 200,000 women, mainly from Korea, were forced into sexual slavery during the war. Japan insists all compensation claims were settled when the two countries normalised bilateral ties in 1965.