Quarrels over partners, gas suppliers and counter-offers made by Russia, which secured a deal with Nabucco partner Bulgaria on a rival pipeline called South Stream, have so far delayed progress on the EU/US project.
Prepirke glede partnera, opskrbljivača plina i protuponuda Rusije, koja je osigurala sporazum s jednim od partnera u Nabuccu, Bugarskom, o suparničkom plinovodu pod nazivom Južni smjer, do sada su odgađali napredak projekta EU/SAD-a.