Staff at the most famous financial institutions in the US are on high alert amid fears of an al-Qaeda terrorist attack following a batch of highly detailed intelligence information.
The New York Stock Exchange is just a few blocks away from Ground Zero
The buildings said to be under threat are those that house the New York Stock Exchange, the World Bank, the International Monetary Fund, Citigroup, and Prudential Financial.
The New York Stock Exchange
This is one of the largest stock exchanges in the world. The New York Stock Exchange (NYSE) is located at 18 Broad Street, at the corner of Wall Street, in the southern tip of Manhattan's financial district.
The NYSE, with its colonnade exterior, is where billions of dollars in shares deals take place every weekday.
The exchange closed down for four days following the September 11 terrorist attacks on the World Trade Center, situated blocks away in the same district.
The NYSE has a back-up facility at an undisclosed location that could take over trading within a day if the main building is damaged, exchange officials have said.
Security measures already in place have included barricades on all sides and multiple checkpoints for entry into the building.
The World Bank has its headquarters in north west Washington DC, just off Pennsylvania Avenue and two blocks from the White House. There, and at five other buildings in the US capital, 7,000 staff are employed.
Workers have been told to report to work on Monday. World Bank buildings have heightened security measures in place.
The bank provides billions of dollars in loans to more than 100 developing countries across the globe.
Its money is used to help fund projects such as sanitation work, irrigation, road and airport runway construction, which boosts the economies of developing nations.
The bank, along with the International Monetary Fund, was originally created to provide stability in the post-war global economy.
International Monetary Fund
Situated in north west Washington DC, close to the World Bank, the International Monetary Fund (IMF) has around 2,400 people working at the site.
"Appropriate security precautions" are in place, an IMF spokesman said.
Both institutions are also located near the George Washington University campus.
The IMF's role is to provide financial support to countries in need of economic reforms and to make sure the money is not squandered by corrupt or incompetent governments.
But both the IMF and the World Bank have come under fire from anti-globalisation campaigners protesting at the extent of the financial control they wield over debt-ridden nations.
Relatively small, the IMF and World Bank are said to be easier to secure than buildings in New York, where the skyscrapers are larger and located in denser city blocks.
Citigroup - the world's biggest bank - has its headquarters in Lexington Avenue, between 53rd and 54th Streets, in New York and provides an array of financial services and products to customers all over the world.
Built in 1978, Citigroup's 59-storey home, famous for its angled roof and aluminium and reflective glass facade, is the third-largest in midtown Manhattan.
The company employs around 25,400 workers in the city.
"In the coming days and weeks you can expect to see additional security measures being implemented," Citigroup has told staff.
Special anti-terror police teams gathered at the Citigroup building on Monday, and New York's mayor, Michael Bloomberg, said similar units would be deployed elsewhere.
Headquarters of financial services giant Prudential Financial and located in a 24-storey building in downtown Newark, New Jersey, about 10 miles west of New York city.
Around 1,600 employees work in the building, with an additional 1,200 working in a building nearby.
Prudential Financial has individual and institutional customers worldwide and its offshoot, The Prudential Insurance Company of America, is one of the largest life insurance companies in the US.
It was founded in 1875 in a basement office in downtown Newark and was the first company in the US to make life insurance available to the working-class.
Police have set up metal fences surrounding the Prudential Plaza building, blocked off two city streets, and armed themselves with assault rifles