North Korea launched at least one ballistic missile on Tuesday morning, according to reports from South Korea and Japan.
The South Korean military's Joint Chiefs of Staff (JCS) said one missile was fired from near Sinpo on North Korea's eastern coast into the East Sea, also known as the Sea of Japan.
The JCS said the launch was detected at 10:17 am, as reported by news agency Yonhap.
Japan's Prime Minister Fumio Kishida meanwhile said two ballistic missiles were fired by Pyongyang, Kyodo reported.
No casualties or damage were reported and the missiles appeared to have already splashed down, a government spokesman cited by Kyodo said.
The launch came after North Korea and South Korea earlier this month restored their direct communications lines.
The telephone and fax lines are central to communication between the two countries, who technically have never ceased hostilities from the Korean War and who do not have embassies in each other's capital cities, Pyongyang and Seoul.
Seoul earlier this month expressed hope for the resumption of inter-Korean dialogue, while North Korean leader Kim Jong Un said the lines were being restored as part of efforts to improve relations and build peace on the Korean Peninsula.
North Korea, which is subject to international sanctions because of its nuclear weapons programme, has caused fresh tension recently with new missile tests.
UN resolutions prohibit North Korea from testing ballistic missiles, which, depending on their design, can also carry a nuclear warhead.
Negotiations between North Korea and the United States have not made any progress since Kim's failed summit with then-US president Donald Trump in Vietnam in February 2019.
Intra-Korean relations have also suffered from the stalemate.