The EU-backed gas group Nabucco said Iraq was its most viable partner for future gas deliveries and stepped up pressure on Azerbaijan, saying Baku should not be tempted by offers based on higher prices alone.

'Iraq is probably the most real, most viable gas supplier,' Dimitar Abadjiev, Nabucco Gas Pipeline International's head of corporate affairs told reporters on Thursday on the sidelines of an energy seminar.

'Iraq is bigger, and it's just on the border with Turkey. It's easier. It's much less dependant on Russia. We've had preliminary talks ... and I'm optimistic,' he said.

Nabucco aims to help wean Europe off its dependency on Russian gas by transporting up to 31 bcm of gas a year from Iraq and the Caspian region to an Austrian hub via Turkey and eastern Europe.

Azerbaijan has been in talks with more than 20 firms and consortiums and will decide later this year which project gets gas from its giant Shah Deniz II gas fields, co-led by BP and Statoil.

The government has said the gas contracts will go to the company that offers the highest price, and the Nabucco and Russian offers are seen as the main contenders.

Russian gas export monopoly Gazprom said recently its competitors would not be able to beat its price for gas from Shah Deniz.

'Price isn't everything,' said Abadjiev.

'They have an interest to diversify consumers and ... this is a real option for them to go to the European market.'

Russia proposes to buy gas on the Azeri order without allowing Azerbaijan to export gas to Europe directly.

The development has worried many EU politicians who say it would only boost the continent's reliance on Russian fuel, which already accounts for around a quarter of Europe's demand.

Abadjiev said Nabucco expected to have the first gas from Iraq, 10 billion bcm, and another 8 billion bcm from Shah Deniz in 2015.

Nabucco's shareholders include Hungary's MOL, Romania's Transgaz, Bulgaria's Bulgargaz, Turkey's Botas, Germany's RWE  and Austria's OMV.-Reuters