A woman walks past a television broadcasting a news report on North Korea firing ballistic missiles, at a railway station in Seoul, South Korea, March 6, 2017. REUTERS/Kim Hong-Ji

SEOUL (Reuters) - South Korea’s acting president Hwang Kyo-ahn said on Monday Seoul should swiftly complete the deployment of a U.S. anti-missile defense system after North Korea launched four missiles earlier in the day.

“We should quickly finish the deployment of THAAD (Terminal High Altitude Area Defense) deployment and acquire a defense system against North Korea’s nuclear missiles,” said Hwang in opening remarks while presiding over a National Security Council meeting after the North’s latest provocation.

North Korea fired four ballistic missiles early on Monday, three of which Japan said landed in its exclusive economic zone, in an apparent retaliation over recent U.S.-South Korean military drills.