The United States has upgraded Japan to include it among countries it judges to fully meet minimum standards for the elimination of human trafficking, according to a State Department report released Thursday.

It was the first time that the United States has ranked Japan on Tier 1, the highest classification on the four-tier list, a senior State Department official said, citing the achievements the Japanese government made during the reporting period that ended in March.

Japan was upgraded from last year's Tier 2, partly due to the launch of an interagency task force to combat "enjo kosai," or compensated dating, and the "JK business," which offers dating services by "joshi kosei," or female high school students, for adult men.

(A girl in a dating service is warned by a police officer in Tokyo)

In the 2018 Trafficking in Persons Report, the department downgraded Myanmar to Tier 3, the lowest level, from the Tier 2 Watch List in last year's report, citing a military crackdown on the Rohingya Muslim minority.

Countries with poor human rights records such as China, North Korea, Russia, Iran and Syria remained on Tier 3.

In launching the 2018 report, Secretary of State Mike Pompeo condemned "tragic examples of forced labor" in Myanmar and North Korea.

Some in Myanmar's military "recruited child soldiers and subjected adults and children from ethnic minority groups to forced labor," Pompeo said.

"Untold number of North Korean citizens are subjected to forced labor overseas by their own government, in many cases with the tacit approval of host governments," he said.

The report hailed Japan for establishing an oversight mechanism for the Technical Intern Training Program, a government-run program designed to foster basic technical skills among foreign workers.

It also backed Japan's accession to the U.N. Convention against Transnational Organized Crime and the 2000 U.N. Trafficking in Persons Protocol.

Other members of the Group of Seven industrialized nations -- Britain, Canada, France, Germany, Italy and the United States -- were among Tier 1 countries.

The report said Myanmar, formerly known as Burma, does not fully meet the minimum standards for the elimination of trafficking and is not making significant efforts to do so.

"Burmese armed forces operations in Rakhine State dislocated hundreds of thousands of Rohingya and members of other ethnic groups, many of whom were subjected to exploitation in Burma, Bangladesh, and elsewhere in the region as a result of their displacement," it said.

According to the United Nations, there are now over 700,000 Rohingya people who have since August last year fled from the northern tip of Rakhine State to neighboring Bangladesh because of a military crackdown.

The world body has criticized the Myanmar military operation against the Rohingya population as "ethnic cleansing."