WASHINGTON (AFP, REUTERS, BLOOMBERG) - In a message ahead of his summit with Chinese leader Xi Jinping, US President Donald Trump said the US will continue to build its military defences against North Korea and reiterated that all options are on the table.

Mr Trump's comments came in a phone call to Japanese Prime Minister Shinzo Abe after Pyongyang fired a ballistic missile into the sea between the Korean peninsula and Japan on Wednesday.

Mr Trump "made clear that the US will continue to strengthen its ability to deter and defend itself and its allies with the full range of its military capabilities", the White House said in a statement.

"The President emphasised that the United States stands with its allies Japan and South Korea in the face of the serious threat that North Korea continues to pose."

Though the White House has previously made similar statements, the call came hours before Mr Trump hosts Chinese President Xi for a two-day summit at his Mar-a-Lago estate in Florida.

A senior White House official said North Korea was a test for the US-Chinese relationship. "The clock is very, very quickly running out," the official said.

Mr Trump has said the US is prepared to go it alone in bringing Pyongyang to heel if China - North Korea's top ally - does not step in.

Beijing says its influence is limited and has repeatedly called for the resumption of diplomatic talks to defuse tensions.

In Tokyo, Mr Abe told reporters he was watching to see how China would respond to Pyongyang after Mr Xi meets Mr Trump.

In another call yesterday, US National Security Adviser H.R. McMaster told his South Korean counterpart that the US remained committed to the deployment of the Terminal High Altitude Area Defence (Thaad) system in South Korea.

The US began deploying the first elements of the system in South Korea last month, despite angry opposition from Beijing.

Mr Trump's top diplomat, Secretary of State Rex Tillerson, in a trip to the region last month, vowed a fresh strategy to counter the North Korean nuclear threat, admitting that all previous efforts had failed.

Meanwhile, the Pentagon has tentatively scheduled for late next month the next intercept test of its Ground-based Midcourse Defence system, the first in nearly three years. It is designed to thwart a nuclear strike by North Korea or Iran.