President Moon Jae-in said on Thursday that South Korea would join with other countries in imposing economic sanctions on Russia over its military operations in Ukraine.

Russian forces fired missiles at several cities in Ukraine and landed troops on its coast on Thursday, officials and media said, after President Vladimir Putin authorized what he called a "special military operation" in the east.

At a National Security Council meeting in Seoul, Moon said that Ukraine's sovereignty, territory and independence must be respected, press secretary Park Soo-hyun told a briefing.

"The use of military force that causes damage of innocent lives cannot be justified in any case," Moon said.

South Korea will support the international community’s efforts to restrain armed aggression and seek a peaceful resolution, including by joining in on economic sanctions, Moon added.

Park did not elaborate on what the sanctions would entail.