Formula One commercial chief Bernie Ecclestone says he is confused by human rights groups criticizing the series for coming to the Azerbaijan capital Baku for this weekend's European Grand Prix.

Human rights organizations have long expressed concern about restrictions on political opposition, and corruption, under the government of Ilham Aliyev, who succeeded his father in 2003. Some rights groups have criticized F1 for going to the country, and others have urged the series to use the race to expose rights issues.

However, Ecclestone said at the street circuit on Thursday that it was a question of definition.

"The moment someone tells me what human rights are, then we can have a look at it, and see when and where it applies," he said.

Azerbaijan, an oil-rich nation of around 10 million people wedged between Iran and Russia on the Caspian Sea, has been trying to burnish its image through hosting international events such as F1, and the Eurovision song contest.

Ecclestone said the contract with Azerbaijan was for seven years with an option for an extension. There is skepticism about the lasting power of new races after the quick arrival and departure of the likes of India and South Korea over the past decade, but the 85-year-old Ecclestone quipped that "there is more chance of them doing seven years than me doing seven years."

The addition of Azerbaijan stretched the schedule to 21 races, and Ecclestone said that may be extended to 22 next year or cut back to 18. There are doubts about the futures of the German and Italian Grands Prix, while he acknowledged "Brazil has a few problems at the moment."

Sources close to Ecclestone recently talked up the possibility of a race in Las Vegas, backed by Chinese investors, but similar reports over the years have come to nothing.