March 5 (UPI) -- Both Japanese and South Korean officials say North Korea launched several missiles into the Sea of Japan.
According to Japanese Prime Minister Shinzo Abe, three of the four missiles landed in Japan's Exclusive Economic Zone.
South Korea and the United States are currently conducting joint military exercises. North Korea has long taken exception to the annual war games, viewing them as prep for an invasion.
"Now that the U.S. imperialists and the South Korean puppet forces again kicked off the dangerous nuclear war drills against the DPRK at its doorstep, our army will counter them with the toughest counteractions," the North Korean government said in a statement issued by state media service KCNA.
The missiles were launched from the Tongchang-ri region of North Korea's North Pyongan Province.
According to South Korea's Joint Chiefs of Staff, the missiles flew 600 miles before landing in the East Sea. Officials suggest at least one of the projectiles could have been an intercontinental ballistic missile.
"These missile launches clearly show that North Korea has developed a new threat," Prime Minister Abe told reporters. "We will collect information and strongly protest to North Korea."
North Korea has been developing technology capable of delivering a missile to the West Coast of the United States, and in a New Year's address, leader Kim Jong Un said North Korea's military had "entered the final stage of preparation for the test launch an intercontinental ballistic missile."