“As a mother, this is much more than a policy priority,” she said at a ceremony to unveil the report. “It is a clarion call into action in defence of the vulnerable and the exploited.”

Secretary of State Rex Tillerson said that the roughly 20 million victims of human trafficking globally illustrate how much more work must be done.

“Regrettably, our challenge is enormous,” Tillerson said.

“Human trafficking is becoming more nuanced and more difficult to identify. Much of these activities are going underground, and they’re going online.”

Watch: Tillerson unveils 2017 US human trafficking report

Malaysia and Qatar moved up to Tier 2, a list of nations making significant efforts to comply, from the Tier 2 Watch List. They join Japan and Singapore in the second highest classification on the four-tier list.

Hong Kong remained on the Tier 2 watch list.

Myanmar and Iraq were also taken off the blacklist of foreign governments identified of having child soldiers, a move that Human Rights Watch said was premature in the case of Myanmar and undermines US credibility in ending the use of children in warfare. The group said the UN has documented child recruitment by Myanmar’s armed forces in 2016.

Myanmar was promoted for its efforts against recruitment of child soldiers and its first prosecution of government officials under a human trafficking law. The Southeast Asia nation had been demoted to the lowest tier last year, shortly after it shifted to civilian government, ending decades of oppressive military rule.

Myanmar’s elevation is a boost for Aung San Suu Kyi’s administration, which is facing growing criticism from human rights groups. The political transition in the Southeast Asian country has been a bumpy one as it wrestles with ethnic conflict and deep-seated discrimination against its minority Rohingya Muslims.

“Congress should be asking tough questions about the State Department’s questionable decisions to upgrade several countries with poor records on trafficking,” said John Sifton of Human Rights Watch.

Indeed, some lawmakers already were. Democrat Senator Robert Menendez said the Trump administration’s first report on trafficking had become a missed opportunity to show the US would hold countries accountable for what they do or don’t do to stop the scourge.

“Alas, this year’s report only further erodes the credibility of that ranking system,” Menendez said. A hawk on Cuba policy, Menendez took particular issue with the decision not to downgrade the island to the lowest rank.

But other lawmakers praised the administration’s handling of the rankings, including Republican Senator Bob Corker, who had questioned the Obama administration’s decision to upgrade several countries in recent years.

The chairman of the Senate Foreign Relations Committee, Corker called this year’s report “a step forward in efforts to improve the transparency and integrity of the rankings.”

The demotion of China was a particular surprise this year, marking the first major, public rebuke of China’s human rights record by the Trump administration, which has generally avoided direct, public criticism of Beijing and other majors on rights issues. The Trump administration has been seeking China’s help to pressure North Korea to give up its nuclear programme, and Tillerson said Tuesday that China’s failure to crack down on forced labour from North Korea was among the reasons it was downgraded.

In the report, the US said that not only was China not meeting minimum standards to stop trafficking, it also was “not making significant efforts to do so.”

The report also said there were indications that China’s government was still complicit in forced labor, including in some drug rehabilitation centres.

The US said China’s efforts to prosecute traffickers had also fallen.

Additional reporting by Reuters