ANKARA/LONDON, Oct 26 (Reuters) - Turkey and Azerbaijan have signed agreements that would bring up to 6 billion cubic metres (bcm) of Caspian natural gas to Turkey by 2017 and allow the transport of another 10 bcm via Turkey to Europe, Turkish officials said on Wednesday.

The long-awaited deal is another step in the development of Azeri gas as an alternative to supplies from Russia's Gazprom , currently the dominant supplier to both Europe and Turkey.

It helps pave the way for the consortium that controls Azerbaijan's Shah Deniz II field to select a pipeline project to transport Azeri gas via Turkey to Europe. A decision is expected next month.

Three international consortia have made bids to build the infrastructure: EU-backed Nabucco, Interconnector-Turkey-Greece-Italy (ITGI) and the Trans-Adriatic Pipeline (TAP).

The Shah Deniz consortium, which includes BP and Azeri energy firm Socar, recently said it was also considering its own project -- the Southeast Europe Pipeline (SEEP) -- which would connect via Turkey and central Europe.

The Shah Deniz field is estimated to contain 1.2 trillion cubic metres of gas. Production of the first phase started in 2006 and has reached 9 bcm a year, of which Turkey is already importing over 6 bcm. The second phase is due to come on stream by 2017.

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