Jamille Bigio is a senior fellow in the Women and Foreign Policy program at the Council on Foreign Relations. Rachel Vogelstein is the Douglas Dillon senior fellow and director of the Women and Foreign Policy program at the Council on Foreign Relations.

Last month, Nigeria’s anti-trafficking agency made a startling announcement: It had collected evidence that some 20,000 Nigerian women and girls are being held in brothels in Mali. Among those discovered were schoolgirls who had been kidnapped and forced into prostitution, reminiscent of the 2014 abduction of 300 Nigerian schoolgirls by Islamist militant group Boko Haram, which prompted the global #BringBackOurGirls campaign.

Today, tens of thousands of women and girls — most between the ages of 16 and 30 — are still awaiting international condemnation of their plight, as well as efforts by the Nigerian government to finally bring them home.

New intelligence suggests that many of the victims were fed false promises of employment in the hospitality industry, only to land in brothels across Africa. Those abducted were discovered on a recent fact-finding mission by Nigeria’s anti-trafficking agency and the International Organization for Migration (IOM), which is now planning additional rescue missions in other west African countries, including Ghana, Burkina Faso and Ivory Coast.

Although the sheer number of victims uncovered in Mali is shocking, the phenomenon of sex trafficking is not: Every year, tens of thousands of Nigerians are trafficked, primarily to Europe and across west Africa. Many leave home voluntarily in search of better-paying jobs, fleeing a country in which 70 percent of the population survives on less than $2 a day. Ninety-one percent of Nigeria’s trafficking victims are women, with 78 percent reporting sexual exploitation at the hands of their traffickers.

Why does the plight of Nigeria’s trafficking victims matter? To be sure, this crime is a tragic violation of basic dignity and rights, one that rightfully inspires moral outcry. But human trafficking is not only a human rights issue — it is also a security challenge. Modern slavery bankrolls operations for transnational crime syndicates and extremist groups, producing an estimated $150 billion annually in profits for perpetrators, making human trafficking one of the world’s most profitable crimes. Nigeria’s criminal networks benefit enormously: In fact, one region of Nigeria — Edo State — is internationally known as a sex-trafficking hub.

Human trafficking also undermines security when this crime is used as a tactic of war. In northern Nigeria and the Lake Chad region, Boko Haram abducts women and girls as a deliberate strategy to generate revenue through ransom payments, exchange prisoners and lure security forces to an ambush. Since 2014, around 2,000 girls and boys have been kidnapped by the group, many of whom have been used as fighters, sex slaves and suicide bombers.

The destruction caused by modern slavery also weakens trust in government, which further erodes stability. In Nigeria, the abduction of tens of thousands of women and girls only exacerbates the perception of the government as ineffective. Declining faith in government, in turn, feeds other grievances against the state, which makes citizens more likely to join nonstate armed groups and less likely to support attempts at economic, social or political reform. The broader social ramifications compound across generations, as children born to girls captured by extremist groups are stigmatized as having “bad blood” and are significantly more likely to be abused and uneducated.

Despite the security implications of human trafficking, too little has been done to address this practice as a threat — not only to human rights, but also to international stability. To address this gap, governments ought to prioritize investigation of the sophisticated criminal and extremist networks that perpetrate this crime. Law enforcement should be better trained to identify trafficking victims, traffickers should be held accountable — as well as any public officials who may be complicit in the crime — and comprehensive care should be offered to survivors.

Given the many ways in which human trafficking fuels transnational crime and extremism, this scourge must be treated as a hazard to both human dignity and international security. Nothing less than our collective safety is at stake.