“We think that 1,500 of us fled, while maybe 150 were killed,” Muhammed recalled on the steps of the makeshift school in northeast Nigeria’s Fufore camp for internally displaced people. Other elder men from his community of Bama nodded, soon turning to discussing the remainder of the town’s 2,000 people, many of who were forced to join the attackers, or did so of their own volition.

After years of low-level and intermittent attacks, including the theft of crops grown on their modest farms, extremists from Boko Haram mounted a more robust assault on Bama in September 2014, leading to an initial exodus of its traders and shutting down commerce in cattle and other agricultural goods. The fleeing traders soon crossed the border into Cameroon, where they alerted the military and prompted an intervention.

The community members sitting on the steps in Fufore were those who stayed until the army arrived. “We followed the military vehicles to Cameroon,” Muhammed (not his real name) told me during a research trip to Adamawa State in December last year. “As we left, they burned down our houses so that Boko Haram could not loot them.”

The group who fled Bama spent just a few months across the border before being forced to return. They are just a handful of the estimated 17,000 refugees to have been sent back. This is despite this process, known as refoulement, violating some of the most steadfast humanitarian conventions and norms, including the 1951 Refugee Convention and subsequent United Nations agreements.

The Organization of African Unity—a precursor to today’s African Union—adopted its own convention on refugees in 1974. Both Cameroon and Nigeria are parties to its requirements, including: “No person shall be subjected by a Member State to measures such as rejection at the frontier, return or expulsion, which would compel him to return to or remain in a territory where his life, physical integrity or liberty would be threatened.”

In short, return must be voluntary and made under conditions of informed consent. Muhammed, and likely all of the thousands of other Nigerian refugees traveling back from Cameroon, did not want to leave and were uncertain about what returning to their home country entailed. Their forced return is thus a major violation of international law. Yet the practice appears to be growing, and threatens to reignite tensions between Nigeria and Cameroon. Currently, however, few advocacy groups are using the term refoulement to refer to the situation, preferring “forced return” to avoid inflaming political tensions. Meanwhile, those that are sent back are granted little autonomy in determining when and where they resettle, aggravating the humanitarian crisis in the region.

The individuals living in Fufore are segregated by gender and must apply for a pass to leave camp to engage in petty trading. They exert little control over their resettlement plans. This alludes to an accelerating humanitarian crisis in which communities escaping Boko Haram are subjected to further victimization. Other refugees sent back from Cameroon told me that they had been forced to pay transport costs of 12,000 Naira (approximately $60 USD) to the Cameroonian army when they originally fled Nigeria. Now being held in the transit camp in Mubi, they said they had been forced to leave behind what little property they had managed to maintain or acquire in Cameroon.

A group of young men, ranging in ages from 18-32, who had fled to Cameroon years ago to avoid conscription into Boko Haram, expressed some appreciation that they are at least able to work and earn a little bit of money while in the Mubi transit camp. “In Cameroon we could not work. We could not acquire any property,” one of the men said.

Cameroon is certainly struggling under the strain of caring for the estimated 64,000 refugees that have fled Boko Haram in recent years. The International Organization for Migration estimates that within the country, the combination of the spillover violence from Boko Haram in northern Cameroon and the influx of Nigerian refugees has displaced 124,000 Cameroonians.

Though Cameroon granted prima facie refugee status to all Nigerians escaping the conflict, including those in the camps and host communities, the increasing number of Boko Haram attacks on Cameroonian soil and the difficulty of providing for the wave of refugees has prompted it to breach its international commitments. The issue is further complicated by the fact that there are also a large number of undocumented Nigerian economic migrants in Cameroon, who can legally be forcibly returned.

There are clear signs of a growing rift between Nigeria and Cameroon. Just over a decade ago, they had come to tentative agreements regarding disputed borders in the Lake Chad region, through the Cameroon-Nigeria Mixed Commission. Now, however, the relationship is typified by the governor of Nigeria’s Adamawa state claiming that some of the returning refugees are not related to the Boko Haram violence, and the Cameroonian government is using security concerns as an excuse to remove those who have fled there. Further disagreement could reignite those long-lasting border tensions, undermine the work of the Multinational Joint Task Force to take on Boko Haram, and jeopardize the cross-border trade on which many communities depend.

Regardless of the legality or the politicization of their return, it is clear that those who have been returned to Nigeria are in a precarious position. When asked whether they would like to remain in Fufore or be resettled in the city of Maiduguri—as many in the camp have been—Muhammed expressed only ambivalence. He is not eager to return to his community because of security concerns, but knows he has little control over his movements. Commenting on the Nigerian government’s hopes of closing all of the country’s internally displaced people camps—which millions rely upon for food, shelter, and medical support—in the early part of 2016, he only shrugs and says, “I am resigned to whatever happens.”

Hilary Matfess is a researcher at the Center for Complex Operations at the National Defense University, Washington, DC.