The police activity was near the 100 block of E. Pratt Street in a parking garage near the T. Rowe Price building.

BALTIMORE — Parts of downtown Baltimore evacuated and closed after police found a suspicious van filled with gasoline on Monday morning.

Police said they responded to a report of the smell of leaking gas coming from a van facing a parking garage near the T. Rowe Price building, WJZ reported.

WJZ, the CBS station in Baltimore, reported several streets were blocked off in the area and caused massive traffic backups.

Monday afternoon, officials said they believe the suspicious van was being used to steal diesel fuel and not a threat to public safety, WJZ reported.

Baltimore Mayor Jack Young said police did not detect a bomb in the van and they were still doing precautionary security sweeps to make sure everyone is safe. At about 4 p.m., he said those security sweeps would likely take several hours.

"We are asking everyone to remain clear of the evacuated area," he tweeted. "Those who have a vehicle parked in the evacuated area, we ask that you please find alternative transportation home."

Several office and commercial buildings were evacuated as well, including the T. Rowe Price building and The Gallery, WJZ reported.

Earlier in the day, Young said the Baltimore City Fire Department had responded to the suspicious vehicle in the 100 block of East Pratt Street and "immediately" issued the evacuation order.

The van had cables coming from it, which investigators originally believed to be a threat, were apparently being used to siphon diesel fuel.

Police said Monday evening the original estimate of 1,000 gallons of fuel found in the van was too high.

President Donald Trump is scheduled to visit Baltimore Thursday. He will speak at a retreat for GOP lawmakers.

A spokeswoman for the retreat told The Baltimore Sun there was no publicly available agenda and that the sessions will be closed to the media.

The newspaper reports several protests are expected outside the hotel where the retreat is to take place.

The visit will come after Trump's attacks on Democratic U.S. Rep. Elijah Cummings and his Baltimore-area district earlier this summer.

Trump called Cummings' majority-black 7th Congressional District a "disgusting, rat and rodent infested mess" where "no human being would want to live." He also called Cummings "racist."

Monday afternoon, Governor Larry Hogan tweeted they were closely monitoring the situation.

"State law enforcement officials are on the scene and assisting with the investigation." he said. "Thank you to the police and first responders who acted quickly to secure the area."