South Korea, the United States and Japan on Friday kicked off a naval exercise aimed at countering North Korean missiles amid growing signs that Pyongyang is ready to test-fire an intercontinental ballistic missile. 

The Navy said Aegis-equipped destroyers from the three countries will take part in the three-day maritime exercise to detect and trace North Korean missiles under simulated conditions. 

The missile warning exercise, third of its kind, is aimed at boost their combined capabilities to respond to the North's evolving military threats. It was held in June and November last year.

It comes amid speculations that the North may launch an ICBM from a mobile launcher at the Panghyon airfield in the northwest, in time for Donald Trump's inauguration as US president. 

(Yonhap)The North has made strides in developing its nuclear and missile programs. In defiance of international sanctions, it conducted two nuclear tests and more than 20 ballistic missile launches last year including intermediate-range Musudan and submarine-launched ballistic missiles.

In October, South Korea and the US agreed to hold regular missile warning exercises also involving Japan during their annual security meetings of defense chiefs, known as the Security Consultative Meeting, in Washington. (Yonhap)