U.S. alliance is "ironclad," as tensions flared anew following North Korea's first ballistic missile test this week since the Trump administration took office in January.

South Korea's military says North Korea has fired several ballistic missiles into the sea. The launch Monday happened hours after South Korean and U.S. troops kicked off their large annual combined drills,

The White House said Tuesday the South Korea-U.S. alliance is "ironclad," as tensions flared anew following North Korea's first ballistic missile test this week since the Trump administration took office in January.