The U.N. Security Council met in emergency session on Sunday to try to cool tensions on the Korean Peninsula, but the five big powers were split on whether to publicly blame North Korea for the crisis.

Pyongyang raised an alert for artillery units along its west coast in what appeared to be its latest move in a growing crisis between the two Koreas, Yonhap news agency said, quoting a South Korean government source. The report was issued ahead of a planned live-fire drill by South Korea.

South Korea’s Defense Ministry offered no immediate comment on the Yonhap report. Bad weather has so far delayed the planned firing drill at a disputed border that has enraged Pyongyang.

Both sides have said they will use military means to defend what they say is their territory off the west coast, raising international concern that the standoff could quickly spiral out of control.

The 15 Security Council members were meeting behind closed doors to try to agree on a statement that Russian U.N. Ambassador Vitaly Churkin said he hoped would send a “restraining signal” to both the North and the South.

Western envoys inside the meeting said the five permanent veto-wielding members were split over whether to blame North Korea for the crisis, as the United States, Britain, and France — along with Japan — demand, or to urge both sides to avoid acts that could deepen the crisis, as Russia and China want.