The North warned Friday that it would strike even harder than before if the South went ahead with its planned drills. Four people died last month in the North's attack on Yeonpyeong Island near the tense sea border.

The US supports South Korea, saying the country has a right to conduct such a military exercise. However, Russia's Foreign Ministry expressed its "extreme concern" Friday over the drills and urged South Korea to cancel it to prevent a further escalation of tensions.

On Saturday, Russia requested an emergency meeting of the UN Security Council on North Korea, UN diplomats said. Council members were discussing the timing of the meeting.

China, the North's key ally, said it is firmly against any acts that could worsen already-high tensions on the Korean Peninsula.

China's Vice Foreign Minister Zhang Zhijun warned in a statement the situation on the Korean Peninsula is "extremely precarious."

The North issued a warning Saturday saying South Korea would face "catastrophe" if it went ahead with the planned drills, the Foreign Ministry said in a statement carried by the official Korean Central News Agency.

South Korean Foreign Ministry spokesman Kim Young-sun said the drills are defensive in nature and are not aimed at stoking regional tensions.

The artillery drills were not expected to be held over the weekend because of bad weather and will be conducted either Monday or Tuesday, a Joint Chiefs of Staff officer said on condition of anonymity.