Chinese Foreign Minister Wang Yi called on North Korea on Wednesday to stop nuclear and missile tests and for the United States and South Korea to stop joint military drills that the isolated North regards as preparation for war.

North Korea launched four ballistic missiles on Monday in response to the military exercises. Wang said those tests and the drills were causing tensions on the Korean Peninsula to increase like two "accelerating trains coming toward each other".

"China's suggestion is, as a first step, for North Korea to suspend nuclear activity, and for the US and South Korea to also suspend large-scale military drills," Wang said at his annual news conference on the sidelines of the meeting of China's parliament in Beijing.

He said this "dual suspension" would allow all sides to return to the negotiating table.

North Korea fired four missiles into the sea off Japan's northwest coast on Monday, angering South Korea and Japan with the latest in a series of ballistic missile and nuclear tests in defiance of United Nations resolutions in recent months.

"Holding nuclear weapons won't bring security, using military force won't be a way out," Wang said. "There remains a chance of resuming talks, there is still hope for peace."

The United States had started to deploy the first elements of its advanced Terminal High Altitude Area Defense (THAAD) anti-missile system to South Korea after the North's latest tests, US Pacific Command said on Tuesday.

The deployment of the anti-missile defence system was likely to deepen a brewing conflict between South Korea and China, which has angrily opposed the THAAD deployment as destroying the regional security balance.

The planned THAAD installation, which South Korea has said would be operational by the end of the year, has led to a diplomatic standoff between China and South Korea.

Chinese authorities have closed nearly two dozen retail stores of South Korea's Lotte Group, which approved a land swap with the military last week to allow it to install the system.

China objects to the THAAD deployment, saying its territory is the target of the system's far-reaching radar. South Korea and the United States have said the missile system is aimed only at curbing North Korean provocations.

China is isolated North Korea's most important supporter, but Beijing has been angered by its repeated missile and nuclear tests and has signed up for increasingly severe UN sanctions against Pyongyang, including suspending coal imports.

China has also rejected accusations from U.S. President Donald Trump that Beijing could be doing more, saying the problem was ultimately between Washington and Pyongyang.