The phone conversation, which Abe told reporters took place at Trump's request, came on the same day that Iranian President Hassan Rouhani wrapped up his two-day visit to Japan.

Rouhani's trip came after deadly protests over fuel price hikes in Iran, where the economy has been hit by US sanctions over Tehran's nuclear programme.

Japan is a key US ally that also maintains close diplomatic and economic ties with Iran, and Abe has tried to build bridges between the two rivals.

Abe did not refer to Iran when he met with reporters just before midnight Saturday, but a Japanese government source told Kyodo that Abe did talk to Trump about his discussions with Rouhani.

The Abe-Trump phone call lasted about 75 minutes, according to Kyodo.

Abe told reporters that he and the US leader talked about what Kyodo described as a "coordinated response" towards North Korea.

Pyongyang has shown frustration at the lack of sanctions relief after three summits with Trump.

Earlier this month it promised a "Christmas gift" if the US did not come up with concessions by the end of the year after it placed a moratorium on long-range missile tests.