The Trump administration blew through at least $40 million to deport roughly 300 migrants—not to their home countries, but to random third-party nations willing to take cash in exchange for warehousing people the U.S. wanted gone.

That works out to more than $133,000 per person.

A new report from Democrats on the Senate Foreign Relations Committee calls the practice “costly, wasteful and poorly monitored,” describing a shadowy network of agreements with countries like Equatorial Guinea, Rwanda, El Salvador, Eswatini, and Palau that operate “largely in the dark.”

The numbers are staggering. El Salvador received about 250 Venezuelan nationals. Equatorial Guinea got 29 deportees. Palau has received zero so far—but still got paid. Lump sum payments to these countries ranged from $4.7 million to $7.5 million each.

And this is just the tip of the iceberg. According to internal administration documents reviewed by the Associated Press, there are 47 third-country agreements at various stages of negotiation. Fifteen have already been concluded.

The waste goes beyond the headline numbers. Democrats found multiple instances of migrants being deported to a third country, only for the U.S. to later pay for another flight to return them to their actual home country. “In many cases, migrants could have been returned directly to their countries of origin, avoiding unnecessary flights and additional costs,” wrote Sen. Jeanne Shaheen and five Democratic colleagues.

During a visit to South Sudan, committee staff found deportees—including people from Vietnam and Mexico—held in a gated house with armed guards.

What are these countries getting in return? The answer appears to be concerning. After striking a deal, South Sudan sent Washington a wish list that included American support for prosecuting an opposition leader and sanctions relief for an official accused of diverting over a billion dollars in public funds.

Shaheen has also raised questions about a $7.5 million payment to Equatorial Guinea that coincided with the administration developing ties with the country’s vice president, Teodoro “Teddy” Nguema Obiang—a man so notorious for corruption that prosecutors in multiple countries have investigated his lavish lifestyle.

Secretary of State Marco Rubio defended the program at a Senate hearing last month. “We’ve arrested people that are members of gangs and we’ve deported them,” he said. “We don’t want gang members in our country.”

Immigration advocacy groups say the policy violates due process rights and strands deportees in countries with long histories of human rights abuses. Meanwhile, taxpayers are footing a $133,000-per-person bill for the privilege.

Related: Watch Hillary Clinton brag about how many people her husband deported