N. KOREA FLIES WARPLANES NEAR S. KOREA BORDER.

SEOUL, SOUTH KOREA • North Korea flew 12 warplanes near its border with South Korea on Thursday, prompting the South to scramble 30 military aircraft in response, Seoul officials said. The highly unusual incident came hours after North Korea fired two ballistic missiles into the sea in its sixth round of missile tests in less than two weeks.

Eight North Korean fighter jets and four bombers flew in formation and were believed to have conducted air-to-surface firing drills, South Korea's military said.

The military said South Korea responded by scrambling 30 fighter jets and other warplanes, though they didn't engage with the North Korean aircraft.

The North Korean planes were probably dozens of kilometres away from the border, South Korean media said.

North Korea has previously sent military aircraft near the border, but Yonhap news agency said this is likely the first time it has mobilized so many warplanes for such a provocative flight and firing exercises.

Tensions have risen sharply on the Korean Peninsula as North Korea's recent barrage of missile tests prompted South Korea, the United States and Japan to conduct joint drills in response.

Earlier Thursday, North Korea launched two shortrange ballistic missiles toward its eastern waters. The launches came after the United States redeployed an aircraft carrier near the Korean Peninsula in response to North Korea's launch of a nuclear-capable missile over Japan earlier this week.

North Korea has conducted a record number of missile tests this year. South Korean officials said the North may further raise tensions by testing an ICBM or conducting its first nuclear test explosion since 2017, following an old pattern of heightening animosities before trying to wrest outside concessions.

U.S., South Korean and Japanese destroyers launched joint drills later Thursday off the Korean Peninsula's east coast.