Russia's envoy to the United Nations says it is seriously concerned there could be a further escalation on the Korean peninsula, where North and South Korea are exchanging threats.
South Korea had planned live-fire drills by its marines starting this weekend on a disputed island, prompting North Korea to threaten stronger retaliation than last month's bombardment of the island that killed four people.
Bad weather has delayed the drill, but South Korea said it had no plans to scrap the drills despite international calls for restraint.
An unofficial US envoy who is visiting North Korea, New Mexico Governor Bill Richardson, has called the situation "a tinderbox".
The Russian envoy to the UN, Vitaly Churkin, has confirmed the UN Security Council will hold an emergency session on Sunday at Russia's request.
China has also expressed concern about the rising tension between North and South Korea saying the situation is "extremely precarious".
Tension on the peninsula is high since North Korea shelled the island of Yeonpyeong in the Yellow Sea on 23 November. Two marines and two civilians were killed.
North Korea said on Friday it would retaliate against the drills with a stronger strike than last month's bombardment.