Ministry of Foreign Affairs in Seoul / Korea Times file

South Korea heightened its anti-terrorism alert status for five of its diplomatic missions by two levels on Thursday, in response to recent intelligence indicating North Korea's attempted acts of terrorist attacks against South Korean diplomats.

The government convened a meeting and decided to raise the state of its four-tier alert from "attention" to the third-highest level of "alert," for the five missions, officials said.

The five missions are the South Korean Embassy in Cambodia, the South Korean Embassy in Laos, the South Korean Embassy in Vietnam, the South Korean Consulate in Vladivostok, and the South Korean Consulate in the northeastern Chinese city of Shenyang.

The alert level is issued when there is likelihood of terrorism, the government said.

In recent years, North Korea has repeatedly reaffirmed its stance against all forms of terrorism.

North Korea has a track record of staging terror attacks against South Korea in the past few decades, including the 1987 midair bombing of a South Korean airliner near Myanmar that killed all 115 people aboard.

The attack prompted the United States to put North Korea on its terrorism blacklist, but Washington removed Pyongyang from the list in 2008 to facilitate talks on ending North Korea's nuclear weapons programs.

In 2017, the U.S. redesignated North Korea as a state sponsor of terrorism. (Yonhap)