El Salvadorian forces are in Haiti on the order of President Nayib Bukele following the abduction of nationals from the Central American country.
Bukele announced a military operation on Wednesday, demanding that the gang leaders and members release the individuals immediately.
"We have a single objective: to bring our four compatriots back home alive, without any harm," the President wrote in a statement.
Bukele said the victims are not combatants but aviation technicians who are in Haiti within the framework of an international mission.
El Salvador's team, he noted, consists only of pilots and technical personnel, whose primary job is to carry out medical evacuations and save lives, not to wage war.
The Head of State decried how the hostages were forcefully taken "in a cowardly manner" while returning after buying food at a market in the area.
Bukele warned the culprits that their attack is nothing compared to what is to come if those held captive are not back alive, saying they still have time to avoid the consequences.
Haitian gangs control an estimated 70% to 90% of the capital, Port-au-Prince, and have expanded their territory into rural areas, amid a severe humanitarian crisis.
In late September, the United Nations Security Council extended the mandate of the Gang Suppression Force in Haiti until March 31, 2027, to suppress the continuing violence by criminal groups.
The GSF, formed in September 2025 to replace the Multinational Security Support, currently has about 1,500 troops, with 4,000 expected to join the contingent.
El Salvador forces storm Haiti to rescue hostages from gangs