Ecclestone says 21 races possible in 2011

(GMM) Bernie Ecclestone on Sunday admitted the F1 calendar could expand to as many as 21 grands prix in 2011.

This year, an equal-record 19 races are scheduled, following the 17 rounds in 2009.

But with India due to join the calendar next year, the F1 chief executive told reporters in Bahrain that the United States could also make a return.

"We can have a look," said the 79-year-old, albeit insisting that there would need to be organizational changes at Indianapolis.

"Twenty one races, no problem."

Ecclestone however said 20 races is more likely.

"It's a round number and easy to remember, I get muddled up now with 19 or 17," he joked.