Japan-US leaders agree to continue pressure on North Korea

Speaking to reporters after the phone call, Prime Minister Abe stressed that the two leaders affirmed that they would maintain pressure until North Korea sought dialogue on the basis that Pyongyang would abandon its nuclear program. "We discussed in detail what we should do at this time to realize the denuclearization of the Korean Peninsula," he said.

This is the second time this month that Prime Minister Abe has had a discussion with President Trump, following a show of unity between North and South Korea at the 2018 Pyeongchang Winter Olympics.

The move comes amid Tokyo's concerns that a thaw in inter-Korean relations could undermine efforts to exert maximum economic and diplomatic pressure on Pyongyang and lead to the start of dialogue on North Korea's terms, which would mean recognizing the country as a nuclear power.

In another development, on the same day, the Japanese Foreign Ministry said that the country had reported to the United Nations (UN) about a suspected transfer of goods between two oil tankers in the East China Sea, an act that violated sanctions against North Korea.

According to the ministry, a Japan Maritime Self-Defense Force aircraft spotted the North Korean tanker Rye Song Gang 1 and another Belize-registered tanker, Wan Heng 11, close together for nearly an hour, about 250 km east of Shanghai, China, on February 13.

Based on monitoring the activities of these two ships, the Japanese government believes that it is likely that the two ships are exchanging goods. Under UN sanctions, the Rye Song Gang 1 is one of eight ships banned from docking at ports worldwide. This is the eighth time in recent months that the Rye Song Gang 1 has been detected engaging in activities believed to be ship-to-ship transfers at sea.

According to Equasis, an online database of maritime information developed by the European Union (EU) and the French Maritime Administration (FMA), the Wan Heng 11, although flying a Belize flag, is owned and managed by a Hong Kong-based company. Ship owners and managers often register their vessels elsewhere to avoid domestic regulations.