MEXICO CITY (AP) — More than 260 charter flights believed to be carrying migrants from Haiti have touched down in Nicaragua in recent months, according to flight data and experts in the region, adding to a historic crush of migration by people hoping to reach the United States.

The flow of migrants has left the Biden administration and Latin American leaders scrambling for solutions, and experts say it’s also being used as leverage by governments like Nicaragua’s to get concessions from the US amid tightening sanctions.

“The Ortega government knows they have few important policy tools at hand to confront the United States, … so they have armed migration as a way to attack,” said Manuel Orozco, director of the migration, remittances and development program at the Inter-American Dialogue. “This is definitely a concrete example of weaponising migration as a foreign policy.”

Nicaragua has long been used as a migratory springboard for people fleeing struggling Caribbean nations like Cuba and Haiti as well as countries as far away as Mauritania in Africa, because it is one of the few countries that doesn’t require visas for many of them to enter.

Such flights from Cuba were already gaining steam late last year amid a historic exodus from the island. In August, Orozco said the Nicaraguan government allowed charter airlines to carry out the flights.

The journeys are not on official air routes, but flight tracking data that has been analyzed by Orozco and The Associated Press shows that 268 of the charter flights went from Haiti to Nicaragua since the beginning of August.

The charter airlines have flown as many as 31,000 people out of Haiti, which would represent nearly 60 per cent of the Haitians arriving to the US border, Orozco’s data shows. Over the same period, some 172 flights have carried 17,000 people from Cuba to Nicaragua.

The AP spoke to three Haitian migrants who were aboard the charter flights, who said they doled out thousands of dollars to leave the poorest country in the hemisphere in hopes of reaching the United States. Orozco said most tickets range between $3,000 and $5,000 a seat.

Things came to a head this weekend, when local media reported that in 48 hours, 27 charter flights from Haiti had landed in Nicaragua. The mounting number of flights comes at a strategic moment for Ortega’s government, said Enrique Martínez, a spokesperson for the dissident group Platform for Democratic Unity.

As Venezuelans make up a big portion of those arriving to the US border, the Biden administration recently negotiated a loosening of sanctions on Venezuela’s government – which have deepened the country’s economic crisis – in exchange for promises of carrying out democratic elections.

Ortega may be hoping for a similar outcome, Martínez said.

The US government and European nations have ratcheted up sanctions on members of Ortega’s family and administration in recent years as he has grown more repressive. His government has driven hundreds of thousands of Nicaraguans to flee abroad and shut down thousands of non-governmental groups and universities in an effort to stifle dissent.

“Ortega is going to use this migration issue to say to the United States that we’re the ones in control,” Martinez said. “ And if they want to stop this, they’re going to have to negotiate.”