Seoul, Mar 7 (IANS): The South Korean government and the ruling party on Tuesday agreed on the need to push for more "effective" sanctions on North Korea after it fired off four ballistic missiles into the the Sea of Japan.

The government and the Liberty Korea Party also agreed to closely communicate with Washington through the two-plus-two consultative institution, a key dialogue channel involving top defence and diplomatic officials, Yonhap News Agency reported.

"(The two sides agreed that) there is a need for additional, strong anti-Pyongyang sanctions," the party's policy chief Lee Hyun-jae told the media.

Lee did not elaborate on additional measures, but he said this matter should be discussed at the UN.

The two sides also agreed to make "active efforts" to put Pyongyang back on the US list of state sponsors of terror in consideration of the recent assassination of its leader Kim Jong-un's half brother Kim Jong-nam.

Kim Jong-nam was killed with the lethal VX nerve agent in an airport in the Malaysian capital of Kuala Lumpur on February 13. Seoul blamed Pyongyang for the killing, but it has denied the claims.

On Monday, North Korea fired off four ballistic missiles in protest against the ongoing military drills between Seoul and Washington.