TOKYO: Japanese Prime Minister Shinzo Abe and US President Donald Trump agreed to keep up pressure on North Korea until Pyongyang abandons its nuclear and missile programs, Japan's foreign ministry said on Thursday.

The two leaders confirmed in phone talks on Wednesday night there would be "no meaningful dialogue" unless North Korea agreed on "complete, verifiable and irreversible denuclearization," the ministry said in its statement.

"Dialogue for the sake of dialogue would be meaningless," Abe told reporters after the phone talks.

South Korea says its president, Moon Jae-in, who has been pushing for a diplomatic solution to the North Korea standoff, was offered a meeting with North Korean leader Kim Jong Un in Pyongyang. The offer was made via Kim's sister, who visited South Korea last week for the Winter Olympics.

U.S. Vice President Mike Pence, who was also in South Korea for the Olympics opening, said on Wednesday the United States was open to talks with Pyongyang but only to convey that it must give up its nuclear weapons.

Separately, Japan reported what it said it had identified as another suspected illegal ship-to-ship transfer involving a U.N. blacklisted vessel.

Japan's Foreign Ministry said it had reported to the United Nations that North Korean-registered tanker, the Rye Song Gang 1, was engaged in a transfer of goods with the Belize-registered tanker "Wan Heng 11", in defiance of U.N. sanctions.

The transfer took place early Tuesday in the East China Sea about 250 km (155 miles) east of Shanghai, the ministry said in a statement issued late on Wednesday.

"Japan must be united with the international community to enhance pressure on North Korea to the maximum degree," it said.

The Rye Song Gang 1 was also spotted last month in the East China Sea engaging in a suspected transfer of goods with the Dominican-flagged tanker "Yuk Tung", which Tokyo also reported to the United Nations.