SEOUL, South Korea — North Korea fired three ballistic missiles from the western town of Hwangju toward Japan shortly after noon on Monday, according to South Korea’s Joint Chiefs of Staff. The launches came on the final day of the Group of 20 summit meeting, where the president of South Korea urged the North’s traditional allies, China and Russia, to help persuade it to end such provocations.

The weapons were all Rodong-class medium-range missiles, which can fly about 620 miles, the Joint Chiefs said. They landed in the Sea of Japan 125 to 155 miles west of Hokkaido, the northernmost of Japan’s main islands, the Japanese Ministry of Defense said.

The launches came four days before the 68th anniversary of the establishment of the North Korean government and a day after a new law went into effect in South Korea aimed at documenting human rights abuses in the North.