North Korea failed in its test-launch of a ballistic missile from submarine after announcing the successful launch of such a missile in May, South Korea's Yonhap news agency reported on Saturday, 28 November.

The test-firing of a KN-11 missile from a submarine was conducted in the East Sea roughly between 2.20 p.m. and 2.40 p.m. (local time); Xinhua quoted an official as saying.

The submarine-launched ballistic missile (SLBM), however, failed to soar from the waters; the official was quoted as saying, noting that debris from the missile found on the ocean surface proved the apparent failure.

If the report is true, it would mark the first test-firing of the SLBM by North Korea since May when capital city Pyongyang made an official announcement of its successful test-launch of a ballistic missile, overseen by top leader Kim Jong Un.

At the time, South Korea expressed deep worries about the test-firing, with President Park Geun-hye describing it as a "serious challenge" to national security and regional stability.

North Korea reportedly imposed a no-navigation zone in eastern waters off the coastal city of Wonsan from 11 November to 7 December.

The report came after Seoul and Pyongyang agreed on Friday, 27 November, to hold a vice ministerial-level meeting on 11 December, at the factory park in North Korea's border city of Kaesong.

The inter-governmental talks are widely expected to improve ties between Seoul and Pyongyang after a surge in tensions in August, caused by an exchange of artillery fire across the border and landmine explosions in border areas that maimed two South Korean soldiers.