North Korea responded on Thursday to claims by US President Donald Trump that he will be holding talks with leader Kim Jong Un later in the year with a broadside of ballistic missiles.

The South Korean military said Pyongyang launched 10 short-range missiles that landed in the sea off North Korea's east coast.

This came a day after Kim's powerful sister, Kim Yo Jong, said Pyongyang was "completely unaware of" plans for discussions.

Trump's announcement on Wednesday that he is in contact with Kim and that the two leaders would meet later in the year appears to have caught Pyongyang off guard. It comes after the US president said the military would scale back annual military drills with South Korea.

The statement by Kim Yo Jong, director of the Central Committee of the Workers' Party of Korea and one of her brother's closest advisers, dismissed Trump's decision to dramatically scale back the 10-day Ulchi Freedom Shield exercises as "unworthy of comment and [we] have no interest in it at all."