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 oko partnera, snabdevača gasom i protivponuda Rusije, koja je obezbedila sporazum sa Bugarskom, jednim od partnera u Nabuku, o rivalskom gasovodu pod nazivom Južni tok, do sada su usporavali napredak tog projekta EU i SAD.