South Korean war veterans on Monday demanded unpaid combat duty allowance, which was paid by the United States to the South Korean government but not to the war veterans, totaling over 9 million US dollars in monetary value of the 1960s.

The Korea's Healthy Security Measures Association (KHSMA), an advocacy group for the war veterans, held a press conference with foreign correspondents in Seoul, attended by hundreds of veterans mostly in their 70s.

KHSMA Chairman Kim Sung Woong, one of the war veterans, told the press conference that the association aimed to receive the unpaid combat allowance that should have been granted to them at least five decades ago.

Kim and his fellow veterans began the demand since 2015 when they first recognized the unpaid combat allowance through a US congressional document, called the Fraser Report.

The Fraser Report was written and submitted by the subcommittee on international organizations of the committee on international relations to the US House of Representatives in 1978.

The page 54 of the disclosed report reads, "the total amount spent by the United States for Korean participation in the Vietnam war came to about 1 billion US dollars. Of this amount, about 925 million dollars entered ROK foreign exchange reserves." ROK refers to South Korea's official name the Republic of Korea (ROK).

Citing William Porter, the former US ambassador to South Korea from 1967 to 1971, the report said South Korean soldiers were "paid at close to US pay levels," but the then South Korean government "paid its troops at levels which were substantially less."

Based on the Fraser Report, the association demanded the South Korean government pay the remaining 925 million US dollars of combat duty allowance in the current monetary value for all the war veterans.

Meanwhile, the veterans cried out for proper compensation for them, especially for the Agent Orange (AO) victims who faced the lives of hardship and poverty.

According to the Ministry of Patriots and Veterans Affairs data given to the KHSMA, the number of victims reached 224,937 as of February, or about 65 percent of the total South Korean soldiers dispatched to the Vietnam war.

The figure included the registered and unregistered death of 67,182 veterans and 157,611 suffering from aftereffects as well as 144 children born with birth defects.

Just about 300 dollars of the monthly war pension was granted to the veterans, and most of the AO victims received less than 1,000 dollars in compensation though they have not been able to do normal economic activity, the KHSMA chairman said.

"(South) Korea's pension and compensation system for war veterans is very underdeveloped... Our aim is to receive the unpaid combat allowance," said the war veteran.

The US forces are known to have used the AO in Vietnam from 1961 to 1971 as herbicide and defoliant. It contains dioxin, the most potent toxin ever known to human beings.

Millions of people are known to have been exposed to toxic chemicals, used by the US forces during the Vietnam war, suffering from deadly diseases such as cancers, nerve disorders, skin disorders and birth defects.