LONDON -- A U.S. naval base in Sicily, Italy, was placed on lockdown on Wednesday due to an "ongoing situation" at an entry control point, officials said.

Naval Air Station Sigonella said in a social media post that a "lockdown/shelter-in-place remains in effect."

"Inbound and outbound traffic at the NAS 2 base entry control points is secured," the post said.

This is a developing story. Please check back for updates.

ABC News' Joe Simonetti contributed to this report.