North Korea test-fired a barrage of short-range ballistic missiles from multiple locations toward the sea on Sunday, South Korea’s military said, extending a provocative streak in weapons demonstrations this year that U.S. and South Korean officials say may culminate with a nuclear test explosion.

Possibly setting a single-day record for North Korean ballistic launches, eight missiles were fired in succession over 35 minutes from at least four different locations, including from western and eastern coastal areas and two inland areas north of and near the capital, Pyongyang, South Korea’s Joint Chiefs of Staff said.

It said the missiles flew 110 to 670 kilometers (68 to 416 miles) at maximum altitudes of 25 to 80 kilometers (15 to 56 miles) while reaching speeds of Mach 3 to 6.

South Korean Joint Chiefs of Staff chairman Gen. Won In-Choul held a video conference about the launches with Gen. Paul LaCamera, an American general who heads the South Korea-U.S. combined forces command in Seoul, and they reaffirmed the allies’ joint defense posture, the JCS said in a statement.