A government watchdog group has promised to investigate the claims.
"If and when we choose to respond, we’ll do so at a time of our choosing."
The tests came three days after U.S., South Korea and Japanese leaders met and agreed to increase cooperation on their ballistic missile defenses.
The North Korean patrol boat crossed the so-called Northern Limit Line at around 11 a.m. Saturday while chasing a Chinese fishing boat.
Load More