Ten US citizens died in the crash of a small plane in Costa Rica on Sunday that also killed the two Costa Rican crew members, the president of the Central American country, Luis Guillermo Solis, said.

"The government of Costa Rica profoundly regrets the deaths of 10 US passengers and Costa Rican pilots in the air accident," which occurred in the country's northwestern Guanacaste region, Solis said in a statement posted to social networks.

The plane burst into flames when it hit the ground, killing all 12 people on board, officials had said earlier.