WRAPUP 2-EU, Turkey sign Nabucco gas transit agreement

* Nabucco "inevitable not impossible" - Barroso

* OMV sees Azeri, Iraqi gas carried

* Turkey says Iran should be included in Nabucco

* Turk PM says Russia gas can be transported too

(Adds analyst comment para 13-15)

By Thomas Grove and Orhan Coskun

ANKARA, July 13 (Reuters) - EU countries and Turkey on Monday signed a transit deal for the Nabucco gas pipeline, aimed at cutting Europe's energy dependence on Russia, a major political step backers say will boost the project.

Transit countries Turkey, Bulgaria, Romania, Hungary and Austria signed the accord for the 7.9 billion euro ($10.99 billion) European Union and United States-backed project, which aims to supply Europe with gas from the Caspian and Middle East.