North Korea fired off four short-range ballistic missiles into the Yellow Sea on Saturday, Seoul said, as the U.S. deployed two B-1B bombers for joint military drills with South Korea.

The South Korean military said it had detected the launches from the Tongrim county area in the country¡¯s northwest, near its border with China, between around 11:32 a.m. and 11:59 a.m., the Yonhap news agency reported.

The missiles flew about 130 kilometers, hitting a maximum altitude of 20 km with a top speed of Mach 5.