U.S. President Donald Trump has directly told Prime Minister Shinzo Abe that he will continue to tolerate North Korea's test-firings of short-range ballistic missiles, according to diplomatic sources, despite unease in Tokyo over the launches.

The reason, Trump explained, was that his administration wants to keep North Korea engaged in negotiations and prevent Washington's talks with Pyongyang from collapsing, the sources said.

The communication between the two leaders came to light Saturday, a day after North Korea carried out its third missile launch in just over a week.