Police have evacuated a number of streets in central London after an unexploded World War II bomb was discovered.

The device was found near Soho's Dean Street by construction workers and police were called at 1:42 p.m. local time on Monday, the Metropolitan Police said.

Thousands of workers were told to leave their buildings and police expanded a cordon across a number of streets in the busy neighborhood. Dozens of police officers were limiting access to the area.

Police are evacuating a large part of Soho after an unexploded WW2 bomb was found just off Dean Street. Cordon is being expanded and several streets are closed off. Dozens of police around and thousands of people being told to leave work.

Umika Verma, a public relations officer, told CNN the incident occurred by the Soho Hotel, opposite her office. "Police said to our receptionist that everyone has to get out," she said.

"We came out of the office and were told to move. No time limit at all was given -- it was just 'get out of the office' immediately. Within five minutes we all had to go."

Soho is a lively part of the British capital, housing a number of businesses, restaurants and bars.

Around two hours after the device was found, police were telling workers at several of the neighborhood's shops and offices to leave work and move away from the area. They also blocked off a number of streets not initially included in the cordoned-off zone.

An employee at Hammer House, on Wardour Street, told CNN: "I saw the cordoned-off area with the police, so I ran back upstairs and said we need to leave."

"We just ran out ... at the beginning people were worried, but now we're more settled."

A large, 250-kilogram (550-pound) WWII bomb was discovered in east London in 2015, but such devices are rarely uncovered in the city.

During the war, German air raids dropped more than 12,000 metric tons of bombs on the capital and killed nearly 30,000 Londoners, according to the Imperial War Museum. (CNN)