STORY: A U.S. aircraft carrier arrived in South Korea on Friday – for the first time in four years.
It will join South Korean ships in a military show of force - which officials say aims to send North Korea a message.
USS Ronald Reagan and ships from its accompanying strike force docked at a naval base in the southern port city of Busan.
U.S. Strike group Commander Rear Admiral Micheal Donnelly said the U.S. is standing firmly by South Korea:
"So, we will leave the messaging to the diplomats. Our interactions with ROK (Republic of Korea) navy are tactically purposeful in developing interoperability to ensure credible combat power."
"And (It's an) opportunity for us to practice our tactics and operations and demonstrate that we stand together."
Its arrival is the biggest development yet – under a new push to have more U.S. nuclear-capable ‘strategic assets’ up and running in the area to deter the North.
South Korean President Yoon Suk-yeol wants more joint military exercises as a warning to Kim Jong-un - after North Korea conducted a record number of missile tests this year.
Analysts believe Pyongyang appears be getting ready to resume nuclear testing for the first time since 2017 – after previous talks failed to persuade North Korea to end its nuclear programme.
In the past – North Korea has denounced previous joint drills as rehearsals for war – and proof of hostility from Washington and Seoul.