Japan’s Kyodo News says the third stage of a three-stage rocket launched by North Korea on Sunday apparently separated from the second stage in the course of falling into the Pacific Ocean.

Kyodo quoted sources familiar with Tokyo-Washington relations as saying Friday that the North’s rocket reached a maximum altitude of 200 kilometers and that the rocket’s third stage appears to have gone down in waters more than three-thousand kilometers away from the launch site of Musudan-ri, North Hamgyeong Province.

The new data differs from Japan’s initial assessment that the second and third stages of the North’s rocket did not separate, but rather fell into the sea while still attached.

Whether or not a country has succeeded in separating the second and third stages of a rocket helps determine the country’s technological capability in building long-range rockets.

The sources say Tokyo and Washington have yet to determine the North’s motives for the launch.