ROME (AP) — A U.S. air base in Italy went on lockdown Wednesday for several hours over an unspecified incident. There were no injuries.

Naval Air Station Sigonella was locked down “due to an ongoing situation,” according to initial posts on the base’s official Facebook page.

The posts suggested that whatever happened occurred at a gate for the base. It urged service members to “avoid traveling on highway SP105 between Marinai Housing Complex” and a part of the base.

The posts didn’t elaborate on what happened. After several hours, a new post described the alert ending at around 11:25 a.m. (1025 GMT) and traffic again being allowed on the base.

“We are grateful to our Navy Security Force personnel for their quick response,” the post added.

U.S. Navy Lt. Andrea Perez, a spokesperson at the base, told The Associated Press there were “no injuries” from the incident and further details would be released later Wednesday.

NAS Sigonella is outside of Catania on the island of Sicily. It’s on a base for the Italian Air Force.

NAS Sigonella hosts U.S. Navy P-8 Poseidon reconnaissance aircraft, as well as MQ-4C Triton drones. There’s also a U.S. Space Force personnel based there who work on identifying possible missile threats in the region.