North Korea fired multiple ballistic missiles into the Sea of Japan early on Sunday, just hours before South Korean President Lee Jae Myung departed for China for talks expected to cover North Korea’s nuclear programme and Taiwan, a topic that has further strained China’s relations with both Japan and South Korea.South Korea’s joint chiefs of staff said it detected several missile launches from the area around North Korea’s capital at about 7:50 am. The missiles flew roughly 900 kilometres. The military further said that South Korea remained ready to respond to any provocation and is closely sharing information with the US and Japan.Japanese defence minister Shinjiro Koizumi also confirmed that North Korea launched at least two missiles, called it “a serious threat to the peace and security of Japan, the region, and the world.” Later in the day, South Korea held an emergency national security council meeting. Officials called on North Korea to halt missile launches, which violate UN Security Council resolutions, and briefed President Lee on the situation.The launches come amid a renewed display of military activity by North Korea in recent weeks. Since negotiations with then US President Donald Trump collapsed in 2019, North Korea has stepped up weapons testing as it seeks to expand its nuclear arsenal. Leader Kim Jong Un has also strengthened ties with Russia and China. South Korean President Lee departed for a four-day visit to China, where he is due to meet President Xi Jinping. Lee’s office said he would urge China to play a constructive role in easing tensions on the Korean Peninsula. South Korea and the US have long pressed Beijing to use its influence over North Korea, though China, along with Russia, has blocked efforts to tighten sanctions in recent years.