American warplanes entered Somali airspace on Friday in support of an attempt by French commandos to rescue a French agent held hostage by Al Shabab militants in Somalia, President Obama told Congress in a letter on Sunday.

The warplanes did not fire any weapons and took no direct part in the operation, the president’s letter said.

The rescue attempt was a failure. The hostage, who used the name Denis Allex, was killed by his captors, and two French soldiers were killed in the raid.

The letter said the American forces “provided limited technical support to the French forces.”

The president’s letter was meant to fulfill a requirement under the War Powers Resolution that he notify Congress within 48 hours after ordering American forces into potentially hostile situations abroad, including entering the territory, waters or airspace of a foreign nation while equipped for combat.