Portugal, France interested in 20th slot on 2013 Formula 1 calendar

The calendar was modified by the FIA at the end of last year to make room for a European race on July 21.

Venues including Spielberg in Austria or Istanbul in Turkey were linked to the slot, but their chances seem to have evaporated and Ecclestone said in December that he expected the calendar to include just 19 events.

Ecclestone now says talks are still ongoing about a possible deal to have 20 races, and revealed the Algarve circuit in Portugal has now entered the frame.

"To be honest, I don't know," said Ecclestone when asked about plans for the July 21 slot.

"There is interest still in France, and now also in Portugal. They want to do it at the new Algarve track.

"For Germany, it would be Nurburgring. Let's see if they can put it together."

Ecclestone admitted, however, that the race was unlikely to be added to the calendar as Formula 1 teams were not keen to have an extra GP.

He added: "If someone wants to have the 20th race, it will happen, if the track is there and okay. We can help [with] organising.

"However, the teams do not seem to be in favour of this race. I doubt it will happen."

The Briton also insisted the calendar will not be expanded beyond 20 races in the future, despite several countries wanting to join.

"No. Twenty [is] the maximum amount," he said.