Citigroup Inc is in the early stages of looking for about 1 million square feet of office space in Manhattan and considering space at the World Trade Center site and at the Hudson Yards, according to two people familiar with the matter.

Citigroup currently leases over 1 million square feet in Manhattan from Boston Properties Inc , including its headquarters at 399 Park Avenue and a building at 601 Lexington Avenue.

It also has a long lease for 2.6 million square feet at 390 Greenwich Street in lower Manhattan. That building is owned by SL Green and SITQ, the real estate unit of Canadian pension fund Caisse de depot et placement du Quebec.

Bloomberg reported earlier on Tuesday that Citigroup was considering leasing space at the World Trade Center site.

Hudson Yards is a 26-acre site on the west side of Manhattan that Related Cos and Oxford Properties are developing for office, retail and residential uses. The development -- sited on top of the rail yards -- is expected to accommodate much of Manhattan's growth over the next 30 years.

Citigroup spokeswoman Shannon Bell said in an email: Although we are always in touch with the real estate community about space that is coming on the market over the next few years, we have no plans to change our footprint in New York City.

(Reporting by Ilaina Jonas and Maria Aspan; editing by Andre Grenon)