Beijing, Sep 25 (IANS): Chinese President Xi Jinping on Wednesday announced the official opening of the country's new $11 billion mega airport, massive enough to contain 98 football fields.

The Daxing International Airport here was formally opened by President Xi on Wednesday morning, the BBC reported.

The airport, said to be the world's largest terminal in a single building, spans 700,000 square metres, says state media outlet China Daily.

Beijing's existing airport is the world's second busiest behind Atlanta, according to the Airport Council.

But Chinese officials said that a new airport was needed to take the pressure off the overcrowded Beijing Capital International Airport.

According to the state-run Global Times newspaper, seven domestic airlines were expected to begin operations out of the new airport on Wednesday.

Airline operators China Southern Airlines and China Eastern Airlines will lead the first flights out of Daxing at 3.45 p.m. local time, said the China News Service.

International carriers including British Airways, Cathay Pacific and Finnair have already announced routes to Daxing.

The new airport was designed by the famed architect Zaha Hadid.

With the opening of the airport, Beijing has joined a group of cities, including New York and London, that have two-long haul international airports.