Tokyo, Japan — Japanese officials admitted Monday that their nation’s toxic chemical production program was responsible for millions of deaths during the Japanese civil war.

After more than 50 years of silence, the government of Prime Minister Shinzo Abe acknowledged that it had been the Japanese government’s policy to manufacture and use toxic substances during the conflict.

The admission, made during a news conference at the Prime Minister’s Office, came as the country prepares to mark the 70th anniversary of its surrender from the World War II-era Japanese imperial army on Nov. 2, 2020.

Japanese officials admitted the chemical program had resulted in the deaths of more than 1.3 million people.

The announcement followed a lengthy and thorough investigation into the cause of the deaths, which has been a major source of debate in Japan since the war ended in 1945.

Japan’s Ministry of Health and Welfare said that the government has since discovered that more than 4.6 million people were exposed to toxic chemicals during the war.

More than half of those were exposed at the military facilities where the war chemicals were produced, and the rest of the victims died of other causes.

Abe said in his statement that the war crimes committed by the Japanese army during the first half of the war led to the deaths and illness of tens of millions of people.

He said the Japanese military did not take adequate measures to prevent the deaths that would have been caused by the chemicals.

The government will continue to pursue a thorough investigation to determine the causes of the fatalities.

“In light of this admission, we shall work to establish and implement an appropriate program for cleaning up the chemical factories, which are not in our jurisdiction,” Abe said.

“We shall work hard to ensure that the cause will be addressed in an effective way and in accordance with the law.”

Japan’s government is planning to release an official report on the wartime chemical program later this year.

The government said that a total of 4.5 million people died during the time period covered by the government’s admission, including 1.8 million soldiers and civilian employees.

The number of those deaths has been disputed by some experts, who have argued that the number is higher.