Kuwait has decided to expel North Korea’s ambassador to the country and four other diplomats, sources have indicated based on intelligence reports.

A Kuwaiti official based in the Persian Gulf region said on Sunday that Pyongyang’s top envoy to Kuwait and four diplomats stationed in Kuwait City would be expelled. The official, who spoke on condition of anonymity, would not elaborate on details of intelligence reports he cited to corroborate his claims.

Kuwait had made a pledge to purge North Korean diplomats in August in a letter sent to the United Nations. There was no report in the Kuwaiti media about the decision and the Information Ministry and the North Korean embassy also declined to comment.

North Korea has its sole diplomatic mission in the Persian Gulf Arab littoral states in Kuwait and the decision to downgrade ties, which will leave the embassy with four staffers, would affect thousands of Pyongyang laborers working in the Persian Gulf Arab countries. The decision could have come under increasing pressure from the United States, which has been locked in a serious stand-off with North Korea over the past three months. It also comes after a trip this month to Washington by Kuwait’s ruling emir, Sheikh Sabah Al Ahmad Al Sabah.

The United States embassy in Kuwait said in a statement on Sunday that the small emirate was a key regional partner on (North Korea) and many other issues, adding that Kuwait has taken positive steps in regards to implementing UN resolutions related to North Korea.

The US has pushed for United Nations resolutions that could further restrict North Korea’s access to financial resources which Washington says are used to strengthen Pyongyang’s missile and nuclear program. Around 50,000 North Korean laborers work overseas, including in the Persian Gulf countries of Kuwait, Oman, Qatar and the United Arab Emirates. UN estimates suggest they send home between $1.2 billion and $2.3 billion a year.

North Korea tested two intercontinental ballistic missiles (ICBM) in July which the experts said could target the mainland US. Pyongyang also tested its most powerful nuclear bomb earlier this month and said it has mastered the technology to fit the bomb on its ICBMs.