SEOUL, Sept. 25 (UPI) -- The United States and South Korea kicked off a joint naval exercise on Monday in response to growing threats from North Korea that include a new nuclear-armed submarine, Seoul's navy said.
The three-day training in the East Sea involves nine U.S. and South Korean vessels, including the USS Shoup Aegis-equipped destroyer, the USS Robert Smalls cruiser, the ROKS Yulgok Yi I destroyer and two Korean submarines.
Boeing's P-8 Poseidon, a maritime patrol and reconnaissance aircraft known as the "submarine killer," is also set to join the exercise. The P-8 uses advanced radar, sonar and optical sensors to hunt for submarines and is armed with weapons including torpedoes and anti-ship missiles.
"This exercise was planned to strengthen South Korea-U.S. joint operation capabilities and interoperability in a situation where North Korea's nuclear and missile threats are becoming more sophisticated, such as the recent launch of a North Korean space launch vehicle and the launch of a new submarine," the South Korean navy said in a statement sent to reporters.
North Korea has announced plans to make a third attempt at placing a military spy satellite into orbit in October, after failed launches in May and August. Pyongyang also unveiled what it called a "tactical nuclear attack submarine" earlier this month.
"This naval training serves as an opportunity for South Korea and the U.S. to effectively deter and respond to North Korea's increasing nuclear and missile threats and further solidify the combined defense posture," Rear Adm. Kim In-ho said in the statement.
The joint drill comes after North Korean leader Kim Jong Un wrapped up a six-day visit to Russia last week amid widespread concern that a weapons deal with Moscow is in the works.
The White House has said that Russia is looking to acquire artillery and other munitions for its war in Ukraine, while North Korea is seeking advanced know-how for its space and missile programs.
South Korean President Yoon Suk Yeol warned last week that Seoul and its allies would not "stand idly by" if Russia gives North Korea technical assistance in developing weapons of mass destruction.
During a keynote address to the United Nations General Assembly, Yoon called the North's nuclear and missile programs an "existential threat" to South Korea and said that any deal between Pyongyang and Moscow would be a "direct provocation."
On Monday, North Korea reacted to Yoon's remarks with a string of insults, calling him a "fool" and a "puppet."
"It is self-evident that such [a] guy with a trash-like head cannot understand the profound and enormous meaning of the development of the DPRK-Russia friendly relations," an unsigned article carried by state-run Korean Central News Agency said.
The Democratic People's Republic of Korea is the official name of North Korea.
"No one in the world would lend an ear to the hysteric fit of puppet traitor Yoon Suk Yeol," the KCNA article added.
South Korea's Unification Ministry called the remarks "vulgar" and not worth a response.
"The fact that North Korea mobilized unidentified individuals to criticize our head of state shows the low level of the North Korean system, which lacks even basic decency and common sense," ministry spokesman Koo Byoung-sam said at a press briefing Monday.