Albanian, Greek and Italian governments confirmed political support for the regional natural gas pipeline by signing a memorandum of understanding on the sidelines of the U.N. General Assembly.
EU Energy Commissioner Gunther Oettinger said the MOU amounted to an in-principle agreement to build the pipeline.
"This is another important step toward our aim to get gas directly from the Caspian region," he said in a statement.
The planned 320-mile pipeline is designed to carry as much as 353 billion cubic feet of natural gas per year from the Azeri waters of the Caspian Sea to European consumers. Land and water surveys for the potential route were approved for the Italian section earlier this month.
By next year, the BP-led group controlling the Shah Deniz gas field in Azerbaijan should decide between Nabucco West and TAP as its transport artery.
Oettinger's office said that, no matter which project is supported, "one or more pipelines" will be part of "an unbroken system" that ties the Caspian Sea to Europe.