El Salvador sent 100 special forces soldiers to Haiti on Thursday to help rescue four missing Salvadoran soldiers, according to the Associated Press, whose report ran on ABC News. The AP cited two officials.

The four men are aviation technicians, NPR and The New York Times reported. They are part of a new UN-backed force fighting gangs in Haiti. Gangs attacked their armored vehicle on Sunday in Croix-des-Bouquets, outside the capital, Port-au-Prince, the outlets reported. The vehicle was hit by explosives and caught fire, the Times said. The four soldiers escaped, but no one has heard from them since.

Haiti's government said on Wednesday that the soldiers had been abducted, the AP and NPR reported. The government called their release "an absolute priority," NPR said.

President Nayib Bukele announced a military operation on Wednesday to rescue them, NPR and the Times reported. He warned gang leaders to return the men "alive, unharmed," NPR said. "Today's attack is nothing compared to what is coming if they do not release the four hostages alive," he wrote on X, according to NPR.

Bukele said the Salvadoran team in Haiti is made up of pilots and technical staff whose main job is medical evacuations, "not to wage war," NPR and the Times reported.

A Salvadoran official said another 100 soldiers were set to go to Haiti on Thursday night, the AP reported. The official said El Salvador believes the four men are still alive.

The attack is the first major one since the new gang suppression force began work, the AP and NPR reported. Police and the force have been fighting armed men in the area since Sunday. Officials have warned residents to stay indoors, the AP said.

No one has claimed responsibility for the attack, the AP and NPR reported.

What we know: El Salvador sent 100 special forces soldiers to Haiti to help find four missing soldiers.
What we don't: Who is holding the men, and whether they are safe.