On Friday, South Korean president Park Geun-hye appeared on television, wearing army fatigues and telling top military commanders that further North Korean provocations “will not be tolerated”.
The situation is being closely watched, with UN chief Ban Ki-moon calling for restraint from both sides and the United States urging Pyongyang to avoid further escalation.
There are nearly 30,000 US troops permanently stationed in South Korea, and the US military’s top officer on Saturday reiterated Washington’s commitment to the defence of its ally.
Calls for calm and restraint have also come from China, the North’s main diplomatic protector and economic supporter.