Twenty-year-old Oxana Rantchev left her home in Russia in 2001 for what she believed was a job as a translator in Cyprus. A few days later, she was found dead after attempting to escape the traffickers who tried to force her into prostitution.

Oxana’s story is the story of modern slavery. Around the world, millions of people are living in bondage. They labor in fields and factories under threat of violence if they try to escape. They work in homes for families that keep them virtually imprisoned. They are forced to work as prostitutes or to beg in the streets. Women, men and children of all ages are often held far from home with no money, no connections and no way to ask for help. They discover too late that they’ve entered a trap of forced labor, sexual exploitation and brutal violence. The United Nations estimates that at least 12 million people worldwide are victims of trafficking. Because they often live and work out of sight, that number is almost certainly too low. More than half of all victims of forced labor are women and girls, compelled into servitude as domestics or sweatshop workers or, like Oxana, forced into prostitution. They face not only the loss of their freedom but also sexual assaults and physical abuses.

To some, human trafficking may seem like a problem limited to other parts of the world. In fact, it occurs in every country, including the United States, and we have a responsibility to fight it just as others do. The destructive effects of trafficking have an impact on all of us. Trafficking weakens legitimate economies, breaks up families, fuels violence, threatens public health and safety, and shreds the social fabric that is necessary for progress. It undermines our long-term efforts to promote peace and prosperity worldwide. And it is an affront to our values and our commitment to human rights.

The Obama administration views the fight against human trafficking, at home and abroad, as an important priority on our foreign policy agenda. The United States funds 140 anti-trafficking programs in nearly 70 countries, as well as 42 domestic task forces that bring state and local authorities together with nongovernmental organizations to combat trafficking. But there is so much more to do.

The problem is particularly urgent now, as local economies around the world reel from the global financial crisis. People are increasingly desperate for the chance to support their families, making them more susceptible to the tricks of ruthless criminals. Economic pressure means more incentive for unscrupulous bosses to squeeze everything they can from vulnerable workers and fewer resources for the organizations and governments trying to stop them.

The State Department’s annual Trafficking in Persons Report, released this week, documents the scope of this challenge in every country. The report underscores the need to address the root causes of human trafficking — including poverty, lax law enforcement and the exploitation of women — and their devastating effects on its victims and their families.

Since 2000, more than half of all countries have enacted laws prohibiting all forms of human trafficking. New partnerships between law enforcement and nongovernmental organizations, including women’s shelters and immigrants’ rights groups, have led to thousands of prosecutions, as well as assistance for many victims.

The 2009 report highlights progress that several countries have made to intensify the fight against human trafficking. In Cyprus, where Oxana Rantchev was trafficked and killed, the government has taken new steps to protect victims. Another example is Costa Rica, long a hub for commercial sex trafficking. This year, it passed an anti-trafficking law; trained nearly 1,000 police, immigration agents and health workers to respond to trafficking; launched a national awareness campaign; and improved efforts to identify and care for victims. This progress is encouraging. Much of it is the result of the hard work of local activists such as Mariliana Morales Berrios, who founded the Rahab Foundation in Costa Rica in 1997 and has helped thousands of trafficking survivors rebuild their lives. Advocates such as Mariliana help spur change from the bottom up that encourages governments to make needed reforms from the top down.

We must build on this work. When I began advocating against trafficking in the 1990s, I saw firsthand what happens to its victims. In Thailand, I held 12-year-olds who had been trafficked and were dying of AIDS. In Eastern Europe, I shared the tears of women who wondered whether they’d ever see their relatives again. The challenge of trafficking demands a comprehensive approach that both brings down criminals and cares for victims. To our strategy of prosecution, protection and prevention, it’s time to add a fourth P: partnerships.

The criminal networks that enslave millions of people cross borders and span continents. Our response must do the same. The United States is committed to building partnerships with governments and organizations around the world, to finding new and more effective ways to take on the scourge of human trafficking. We want to support our partners in their efforts and find ways to improve our own.

Human trafficking flourishes in the shadows and demands attention, commitment and passion from all of us. We are determined to build on our past success and advance progress in the weeks, months and years ahead. Together, we must hold a light to every corner of the globe and help build a world in which no one is enslaved.

The writer is secretary of state.