Photo released by North Korea's official Korean Central News Agency on Wednesday shows North Korean leader Kim Jong-un (right) on a horse as he visits battle sites at Mount Paektu, Ryanggang. Photo: AFP

North Korea fired two unidentified projectiles on Monday, the South's military said, weeks after Pyongyang declared its moratorium on long-range missile tests over.

The move comes as nuclear negotiations with the US are at a standstill and as a unilateral deadline Pyongyang set Washington to offer it fresh concessions on sanctions relief expired.

The two devices were fired eastwards over the sea from the Wonsan area on the east coast, the South's Joint Chiefs of Staff said.

"The military is monitoring for additional launches and maintaining readiness," the statement added.

The latest launches come as Pyongyang tries to prevent a nationwide coronavirus outbreak, which analysts say would wreak havoc in the country. 

North Korea has not reported a single case of the coronavirus, which has killed more than 3,000 people and infected over 88,000 in dozens of countries since it emerged.

Seoul and Washington last week said they will postpone forthcoming joint military exercises after South Korea declared its highest "severe" alert level over the coronavirus.

The US has 28,500 troops in South Korea, many of them based at Camp Humphreys in Pyeongtaek - the biggest overseas US military facility.

AFP