North Korea has fired a second ballistic missile into the sea off the coast of South Korea, the South’s military said.

Officials said in a statement that the launch was made on Monday morning without giving further details.

The reported launch came hours after Seoul reported that North Korea had conducted a short-range ballistic missile test into the sea in a resumption of its weapons-testing activities.

Observers said the North’s back-to-back launches were likely to be a protest against moves by South Korea and the US to bolster their nuclear deterrence plans in the face of Pyongyang’s evolving nuclear threats.