Pyongyang's latest display of firepower comes ahead of South Korean President Lee's meeting with China's Xi Jinping.

North Korea fired multiple ballistic missiles from Pyongyang towards the sea off its east coast on Sunday, South Korea's military said.

The missile launch is North Korea's first in two months, and first of the new year.

The latest test came just hours before South Korean President Lee Jae Myung's visit to China for a summit.

What do we know about North Korea's missile launch?

Several ballistic missile launches were detected from North Korea's capital region at around 7.50 a.m., South Korean military officials said.

The missiles were fired towards the East Sea, which is also known as the Sea of Japan.

Seoul said the missiles flew about 900 kilometers (560 miles) and that South Korea and US authorities were closely watching the launches.

"The military is maintaining a full readiness posture, having strengthened surveillance and vigilance against possible additional launches," Seoul said.

Japan also said its military had detected ballistic missiles, with Defense Minister Shinjiro Koizumi saying that at least two missile launches by North Korea have been confirmed.

"They are a serious problem, threatening the peace and security of our nation, the region and the world,” Koizumi told reporters.

Why are North Korea's missile launches significant?

The last time Pyongyang fired ballistic missiles was in November, when US President Donald Trump approved South Korea's plan to build a nuclear-powered submarine.

The latest launch comes ahead of Lee Jae Myung's trip Sunday to China, where he will meet with Xi Jinping. Beijing is one of North Korea's key backers.

Sunday's launch also comes on the heels of the US capture of Venezuela, one of Pyongyang's few allies.

Some observers have said that the US strikes on Venezuela could be a reason for North Korea launching the missiles.

"They likely fear that if the United States so chooses, it could launch a precision strike at any moment, threatening the regime's survival," Hong Min, an analyst at the Korea Institute for National Unification, told the AFP news agency.

"The underlying message is likely that attacking North Korea would not be as easy as a strike on Venezuela," he added.