U.S. Secretary of State John Kerry speaks during a ceremony releasing the 2014 Trafficking in Persons Report at the State Department on June 20 in Washington, D.C. (Win McNamee/Getty Images)

The U.S. State Department published its 2014 Trafficking in Persons (TIP) report today in which it downgraded the status of a number of key U.S. allies. The report grades governments around the world on how they're tackling human trafficking. "It is a reminder of what happens in many dark places that need light," said Secretary of State John Kerry at a ceremony in Washington announcing the report's release. "And we have a responsibility to try to bring that light to these individuals and to these places."

The most eye-catching development was the U.S.'s shifting of Thailand to "Tier 3", the lowest rung in the TIP's scale. According to Reuters, Thai officials had been confident that their status would be upgraded; instead Thailand was consigned to the same category as Saudi Arabia, North Korea, Syria and others considered as centers for worker abuses and human trafficking.

A recent expose by the Guardian on Thailand's vast shrimping industry, which sources food to markets in the U.S. and E.U., found a preponderance of migrant workers toiling in slave-like circumstances on fishing ships. Thai authorities have also been accused of neglecting or mistreating trafficked migrants, some from vulnerable minority communities, who arrive in the country as asylum seekers. Thailand, a longstanding U.S. ally in Asia, may now face U.S. aid cuts and a dip in foreign investment.

Kerry did not address Thailand directly in his remarks. But rights groups weighed in. "Today’s decision by the United States Department of State to downgrade Thailand is the right course of action given the damning evidence that has continued to emerge throughout 2013 and 2014," said Steve Trent, executive director of the Environmental Justice Foundation, in a statement.

Human Rights Watch used the occasion to spotlight the widespread practice of forced labor in Uzbekistan, another country with close security ties to the U.S. Uzbekistan also was placed in the lowest "Tier 3" category. “This decision is an important step toward holding [the Uzbek government] accountable for the abysmal reality in Uzbekistan’s cotton fields,” said Steve Swerdlow, Central Asia researcher at Human Rights Watch. “Over a million Uzbek adults and children are forced to harvest cotton for weeks on end every autumn in abusive conditions on threat of punishment.”

The U.S. accorded itself a top-ranked "Tier 1" listing, but some rights groups say that's no cause for celebration, given the significant trafficking horror stories that still emerge in the U.S. “The United States must lead by example but unfortunately we don't see an aggressive, well-funded effort that is on par with the scope of the human trafficking problem within our own borders," said Melysa Sperber, director of the Alliance to End Slavery and Trafficking.

The original version of this story mistakenly identified Qatar as a country listed in the "Tier 3" category. It is actually one category above in the "Tier 2 Watch List."