North Korea conducted an artillery fire drill Saturday that could target its rival Korea’s heavily populated capital after Washington and Seoul kicked off joint military aerial exercises on Monday despite Pyongyang’s rebuke. 

North Korea’s mechanised troops held an “artillery fire competition” to boost the country’s “mobile artillery combat capabilities,” state-run Korean Central News Agency said Sunday. The country’s leader, Kim Jong Un, didn’t watch the drill, although Pak Jong Chon, a member of the Presidium of the Political Bureau, inspected the fire competition, the state media reported. 

Much of North Korea’s artillery forces are deployed along the border with South Korea and are aimed at the South’s capital, home of about 10 million people and located about 40 kilometers (25 miles) from the border. 

The US and South Korea conducted a five-day joint air defense exercise from Monday that involved some 200 aircraft, South Korea’s Yonhap news agency reported. North Korea has claimed that the international community has a double standard, and only criticizes Pyongyang’s military drills.