The declaration of support by Russian President Vladimir Putin, Greek Prime Minister Costas Karamanlis, and Bulgarian President Georgi Parvanov paves the way for an intergovernmental agreement by the end of this year.
The project will funnel Russian oil directly to southeastern Europe, bypassing Turkey's busy Bosphorus Strait. Russian oil will initially be transported by sea to the Bulgarian port of Burgas, and from there by pipeline to the Greek Aegean Sea port of Alexandroupolis.
From Athens, Putin is due to travel on to Cape Town to start an official visit to South Africa.
(Reuters, AP, ITAR-TASS)