US Secretary of State Mike Pompeo, Washington’s lead negotiator on North Korean denuclearization, said on Saturday that he believes Russia is violating international sanctions against North Korea.

“I want to remind every nation that has supported these resolutions that this is a serious issue and something that we will discuss with Moscow,” Pompeo told a news conference in Singapore, Reuters reported, “We expect the Russians and all countries to abide by the U.N. Security Council resolutions and enforce sanctions on North Korea.”

Pompeo is in Singapore for meetings of the foreign ministers of the Association of Southeast Asian Nations (ASEAN) as well as China, Russia, Japan and South Korea. His presence in Singapore follows the promising June summit in the island state between North Korea leader Kim Jong-un and US President Donald Trump.

However, since that summit, and despite goodwill gestures from Kim, such as the dismantlement of a satellite launch site and the return of apparent US war remains, no mutually-agreed upon denuclearization process has yet started.

Against this background, there have been reports that China and Russia are easing off sanctions pressure.

Is Moscow breaking ranks?

On Thursday, US newspaper the Wall St Journal, citing Russian Interior Ministry records – which the report indicates may have been obtained, and then leaked, by US government officials – wrote that Russia has issued more than 10,000 visas for North Korean workers since the UN Security Council called for governments not to issue new work permits to persons from the heavily sanctioned state.

Many of the companies hiring North Koreans are joint ventures with North Korean bodies, the Journal reported, which would also be a violation of related sanctions.

Pompeo said that he has reason to believe the reports, according to Reuters. Russia has denied the Wall Street Journal report, and has also denied that Moscow was flouting U.N. restrictions on oil supplies to North Korea.

HR has  been a key North Korean export for years with many textile and seafood processing factories in northeast China employing North Koreans. North Korean workers have also customarily worked in the Russian Far East in areas such as logging and construction.

According to Russian data cited in the Journal report, most of the North Korean laborers in Russia were working in construction-related fields, such as plastering, masonry, tiling and painting.

Since last year, both Chinese and Russian vessels are believed to have supplied North Korean vessels with fuel shipments on the high seas in defiance of sanctions, though it is not known if these activities had been approved by Beijing and Moscow.

North Korea and the diplomatic merry go round

North Korean Foreign Minister Ri Yong Ho is also attending the Singapore event. Pompeo said he had not met Ri. US Ambassador to Manila, and formerly to Seoul, Sung Kim – a key negotiator on the nuclear issue –  said he had no plans to meet the North Koreans in Singapore, according to Reuters.

Japanese Foreign  Minister Taro Kono told Japanese reporters that he had met Ri on Friday night and had reiterated Japan’s views and basic stances. According to the Asahi newspaper, Kono told Ri that Japanese Prime Minister Shinzo Abe seeks a summit with Kim, but did not tell the reporters what Ri’s response was.

Ri also met South Korean Foreign Minister Kang Kyung-wha – but only on the sidelines of the summit at a gala dinner. The two did not engage in formal meetings. According to South Korea’s Yonhap news agency, Ri had declined official talks, saying that the time was not right.

The formerly isolated and diplomatically reclusive Kim has been engaged in a spate of summits this year. He has has met Trump once, and Chinese President Xi Jinping and South Korean President Moon Jae-in twice each. He has also agreed to meet Moon again this autumn.

However, despite invitations issued by Russian President Vladimir Putin, it is not known if Kim will visit Moscow or Vladivostok, for the annual Russian Far East Economic Forum in September. However, North Korean aircraft have recently been spotted in Vladivostok, including Kim’s own official aircraft, according to reports in South Korea.

Moon and Abe are also expected to attend the Vladivostok meeting, raising the possibility of a quadrilateral summit.