A leading Japanese daily says North Korea fired three short-range ballistic missiles into the East Sea on Wednesday.

The Sankei Shimbun quoted several Japanese government sources as saying on Friday that the North fired the missiles toward the East Sea on Wednesday morning. The report said the North apparently fired the missiles to test improved models.

The North is currently developing ground-to-air KN-06 missiles and short-range ballistic KN-02 missiles, which are an upgraded version of missiles produced by the former Soviet Union.

The North also fired two short-range missiles into the sea off the North’s east coast just hours after the death of the North Korean leader was announced on December 19th.