Prosecutors said Tuesday they have indicted nine people, including a lieutenant colonel, on charges of irregularities in the signing of contracts for the military's coastal surveillance equipment and submarine simulator.

The Seoul Central District Prosecutors' Office said a former executive of a local defense firm, identified only by his surname Bae, is suspected of forging test results to sign a contract with the Defense Acquisition Program Administration. The contract was for a complex surveillance system to be set up along the country's coastline in 2013 to detect unidentified boats operating in South Korean waters.

When the company won the contract, the 48-year-old allegedly siphoned off some 550 million won ($476,000) in August 2013 by exaggerating the unit price.

A 42-year-old army official, surnamed Lee, is suspected of giving favors to the defense firm, despite knowing that the reports were fabricated. Lee and a 51-year-old lieutenant colonel, surnamed Choi, are also accused of leaking military secrets to the company.

Four other current and former officials of the company were indicted over their alleged involvement in the irregularities.

A former chief of the defense firm and the head of its contractor were also indicted on charges of exaggerating the development cost of the submarine simulator in November 2012.(Yonhap)