(Adds report of no victims, no immediate comment from Navy, details on barges)
Oct 18 (Reuters) - Police in Portsmouth, Virginia, were investigating a report of an active shooter, the department said in a post on Twitter on Thursday.
Dispatchers received an emergency 911 call at 11:46 a.m. ET, police said, adding that no further information was available.
Officials could not confirm whether the report was legitimate, the Virginian-Pilot newspaper reported, citing Portsmouth police Lieutenant B.K. Hall. Hall said no victims have been found, the paper said.
The incident involved Navy personnel near a berthing barge by General Dynamics Corp's facility in Portsmouth, local news media reported, citing a company official.
The Navy had no immediate comment. Berthing barges house crew members when their ship or submarine is in port or dry-dock undergoing maintenance or repair.
Part of the port remained open, but a service area was closed, the Port of Virginia said by Twitter.
The General Dynamics facility was on lockdown and employees have evacuated it, local television station WAVY-TV said.
The station showed images of police casually strolling around the gate to the facility.
A representative for the aerospace and defense company could not immediately be reached for comment. Portsmouth police and Virginia State Police representatives did not immediately respond to requests for comment.
Portsmouth is 3 miles (5 km) from Norfolk, across the Elizabeth River.
The NASSCO-Norfolk facility comprises two shipyards bought by San Diego-based General Dynamics' National Steel and Shipbuilding Co (NASSCO) between 2011 and 2012, according to the company's website. Both yards carry out work for the Navy and others.
The facility has five deepwater piers, a 40,000-ton dry dock, thousands of square feet of industrial shops, and a workforce of more than 1,000, according to the company's website. (Reporting by Suzannah Gonzales in Chicago Additional reporting by Andrew Hay in Taos, New Mexico, Bernie Woodall in Fort Lauderdale, Florida and Daniel Wallis in New York; Editing by Jessica Resnick-Ault and Jonathan Oatis)