Hundreds of documents meant to ensure the safety of South Korea's nuclear reactors have been forged, a top official said Thursday.

Kim Dong-yeon, a minister at the Prime Minister's Office, said government officials combed through about 22,000 test results for parts used in 20 reactors that are currently online. Among the test results, 277 documents or 1.2 percent were fabricated, said Kim.

A separate probe of 218,000 out of 275,000 test results for eight other reactors also showed that 2,010 documents or 0.9 percent were forged, said Kim. The eight reactors include five reactors that are being built and three reactors whose operations were suspended.

The latest probe comes amid lingering concerns about the safety of nuclear reactors in South Korea, especially in light of Japan's Fukushima accident. South Korea operates 23 reactors, supplying about 30 percent of its total electricity consumption.

South Korean reactors abruptly stopped operating on a total of 128 occasions over the past decade due to defective parts, though no accidents were blamed on the parts that had forged quality warranties, said Kim.

South Korea is pushing to either reexamine or replace parts whose test results are confirmed to have been fabricated, said Kim.

Meanwhile, a total of 100 officials, including those from private companies and state-run companies, were indicted in connection with the scandal, he said. (Yonhap News)