The United States, South Korea, and Japan navies staged trilateral anti-submarine exercises for the first time in five years today, amid tension over North Korea's series of missile tests.
According to media reports, the drills were held in international waters off the Korean peninsula's east coast.
The South Korean navy in a statement has said that the exercises are designed to improve their capability to respond to increasing North Korean submarine threats, including its
submarine-launched ballistic missiles.
However, the US navy said, the drills will enhance inter-operability and tactical and technical coordination between the three countries.
It happened just a day after North Korea fired two ballistic missiles into the sea off its east coast.
Thursday's test was the third such launch in five days by the North, which has fired an unprecedented number of missiles this year.