WASHINGTON (Reuters) -The Federal Aviation Administration said on Tuesday it will bar U.S. airlines from operating in Haiti for 30 days after three commercial jetliners were struck by gunfire on Monday.

The FBI said separately it was investigating the incidents and working with law enforcement partners.

The FAA issued a Notice to Air Mission prohibiting U.S. airlines from operating flights in the Haiti's territory and airspace below 10,000 feet (3,048 meters) for 30 days, citing "safety-of-flight risks associated with ongoing security instability."

American Airlines said on Tuesday that it was the third U.S. airline to have a plane struck by a bullet in Haiti. The carrier said American Flight 819 landed in Miami on Monday from Port-au-Prince and a post-flight inspection indicated the exterior of the aircraft had been impacted by a bullet.

"We are working closely with all relevant authorities to investigate this incident," American Airlines said.

On Monday, a Spirit Airlines flight destined for the Haitian capital was struck by gunfire, forcing it to be diverted to the neighboring Dominican Republic, while a JetBlue Airways flight returning from Port-au-Prince was discovered with bullet damage after arriving in New York.

Spirit said its plane had been damaged and taken out of commission upon landing in the northern Dominican city of Santiago. A flight attendant was injured in the incident, while no passengers were harmed.

American Airlines said it was suspending service to Haiti through Feb. 12.

Armed gangs in Haiti's capital have shot at aircraft in recent weeks as the security situation deteriorates. Last month, a U.N. helicopter was hit by gunfire over Port-au-Prince.

On Monday, Haitian Prime Minister Alix Didier Fils-Aime took office pledging to improve security. Fils-Aime was appointed by the Caribbean island nation's transitional council over the weekend to succeed Garry Conille, who only lasted in the role six months.

(Reporting by David ShepardsonEditing by Sandra Maler)

By David Shepardson