The USS Carl Vinson berthed in the southern port of Busan as US Secretary of State Rex Tillerson began a tour of the region, where tensions have spiked in recent weeks with missile launches from the nuclear-armed North and the brazen assassination of Kim Jong-Un's half-brother in Malaysia.
Pyongyang has long condemned the annual joint drills, which involve tens of thousands of troops, as provocative rehearsals for invasion, while Seoul and Washington insist they are purely defensive in nature.
"The importance of the exercise is to continue to build our alliance and our relationship and strengthen that working relationship and interoperability between our ships," Rear Admiral James Kilby, commander of USS Carl Vinson Carrier Strike Group 1, told journalists.
He said training opportunities in the region were "world-class" and allow the US to "build upon our strong alliance" with the South.
More From This Section
In an apparent response to the exercises, Pyongyang launched four ballistic missiles last week -- with three landing in waters that are part of Tokyo's exclusive economic zone -- and described them as a drill for an attack on US bases in Japan.
Visiting the headquarters of an army unit early this month, the North's leader Kim Jong-Un praised his troops for their "vigilance against the US and South Korean enemy forces that are making frantic efforts for invasion", according to the North's official KCNA news agency.
Pyongyang is widely seen as behind the murder of Kim's half-brother Kim Jong-Nam in Kuala Lumpur last month, by two women using a banned nerve agent.