North Korea fired two unidentified projectiles into the East Sea on Friday, South Korea’s military said.

It was the sixth round of launches in recent weeks in protest at ongoing South-Korean-US joint military drills. North Korean leader Kim Jong Un has described the tests as a “solemn warning” to the South.

The projectiles were fired from its eastern coastal county of Tongchon in Kangwon province earlier in the day, Yonhap News Agency quoted Seoul’s Joint Chiefs of Staff (JCS) as saying.

No other details were immediately known, including their type, flight range and maximum altitude.

“Our military is monitoring the situation in case of additional launches while maintaining a readiness posture,” the JCS said in a statement.

The latest launch came six days after North Korea fired two projectiles believed to be short-range ballistic missiles into the East Sea.

In a speech on Thursday marking the anniversary of Korea’s liberation from Japan’s 1910-45 rule, Moon outlined a goal of “achieving peace and unification by 2045”, although his single five-year term presidency ends in 2022.

“His speech deserves the comments ‘foolish commemorative speech’,” the North said in its statement.

“We have nothing to talk any more with the south Korean authorities nor have any idea to sit with them again,” it added.

Moon has played down the North’s recent tests, even suggesting potential inter-Korean economic projects as a way to tackle the South’s ongoing trade row with Japan, which has led critics to accuse him of having a “peace fantasy”.

The North is banned from ballistic missile launches under UN Security Council resolutions.

Seoul’s Joint Chiefs of Staff said the South was “monitoring the situation in case of additional launches while maintaining a readiness posture”.

North Korea has repeatedly issued warnings against the combined military exercise between South Korea and the US, threatening that it would seek “a new way” rather than engagement if Seoul goes ahead with such a rehearsal for invasion.

In a letter to US President Donald Trump last week, North Korean leader Kim Jong-un also voiced his displeasure over the ongoing exercises that began on Monday.