The Japan Coast Guard has issued a navigation alert for vessels that sail in the East Sea and the northern Pacific Ocean.

The Japanese agency issued the alert late Thursday shortly after North Korea announced that it would launch a communications satellite early next month.

The navigation alert was issued for the area that extends from 130 kilometers south of Akita Prefecture to the northern part of the Pacific some two-thousand kilometers from Japan’s mainland.

The Japan Coast Guard urged ships to exercise added caution when passing through the area between April fourth and eighth, which is the launch window released by Pyongyang.

Meanwhile, the Japanese government reiterated that the North would be violating a U.N. resolution if it launches a satellite, stressing that the international body should reinforce sanctions against North Korea in the event a launch takes place.

Tokyo said it is considering intercepting if the rocket heads toward Japan.