Seoul’s spy agency warned Wednesday that North Korean cybercriminals are carrying out cyberattacks against South Korean shipbuilders to boost recent efforts to enhance the country’s naval capabilities.

The National Intelligence Service (NIS) said in a press release that an unspecified North Korean threat group made “multiple hacking attempts” against leading shipbuilders between August and September, indicating that this campaign will likely continue in the future.

The NIS linked the campaign to Kim Jong Un’s push to upgrade North Korea’s navy and develop “mid-to-large-sized warships,” but did not provide details about what the attackers tried to obtain to further these goals.