WASHINGTON -- In a new report, the U.S. State Department says Belarus, Iran, Russia, and Turkmenistan remain among the worst offenders of human trafficking and forced labor.

The department’s annual Trafficking In Persons report, which is aimed at curbing human trafficking, was unveiled in a ceremony in Washington on June 28 by Secretary of State Mike Pompeo and presidential adviser Ivanka Trump.

It evaluates 187 countries and territories and ranks them into four tiers (Tier 1, Tier 2, Tier 2 Watch List, and Tier 3), with Tier 1 being the best and Tier 3 the worst.

Russia, Belarus, Iran, and Turkmenistan were among 22 countries ranked as Tier 3. Others included Burma (also known as Myanmar), China, North Korea, Syria, and Venezuela.

The Russian government “does not fully meet the minimum standards for the elimination of trafficking and is not making significant efforts to do so,” the 2018 Trafficking In Persons report stated as a reason why Russia remained among the worst offenders for the sixth year in a row.

It said Russian authorities “routinely detained and deported potential forced labor victims without screening for signs of exploitation, and prosecuted victims forced into prostitution for prostitution offenses.”

It urged Moscow to investigate allegations and prevent the use of forced labor in construction projects, screen for trafficking indicators before deporting or repatriating migrants, and to establish formal national procedures to aid law enforcement officials.

The report said Belarus, a Tier 3 country since 2015, "maintained policies that actively compelled the forced labor of its citizens, including civil servants, students, part-time workers, and the unemployed, citizens suffering from drug or alcohol dependency, and, at times, critics of the government, among others.”

In Iran, which has been Tier 3 since at least 2011, “trafficking victims reportedly continued to face severe punishment, including death, for unlawful acts committed as a direct result of being subjected to trafficking."

It also accused the government of providing financial support to militias fighting in Iraq that recruited and used child soldiers.

It said Turkmenistan, which remained on the Tier 3 list for the third consecutive year, continued to use “the forced labor of reportedly tens of thousands of its adult citizens in the annual cotton harvest and in preparation for the Asian Indoor and Martial Arts Games” that the country hosted in September 2017.

Pakistan, meanwhile, was upgraded from Tier 3 to Tier 2, with the report crediting Islamabad with “making significant efforts” to tackle trafficking.

It said Pakistan, which had been Tier 3 from 2014-17, “demonstrated increasing efforts by increasing the number of victims it identified and investigations and prosecutions of sex trafficking.”

It cautioned, though, that the country’s overall law enforcement efforts on labor trafficking remained “inadequate compared with the scale of the problem.”

The State Department ranked Georgia as the only former Soviet republic to be a Tier 1 country, a category that comprises 39 countries.

In the middle are the Tier 2 countries, defined as those that do not fully meet the minimum standards but are making significant efforts to bring themselves into compliance.

These include Afghanistan, Albania, Armenia, Azerbaijan, Kazakhstan, Kosovo, Macedonia, Moldova, Pakistan, Romania, and Serbia.

The report listed 43 countries in danger of being downgraded to Tier 3 in future years. The Tier 2 Watch List includes Bosnia-Herzegovina, Kyrgyzstan, Montenegro, Tajikistan, and Uzbekistan, along with EU member Hungary.