The European Union said Serbia needs to get in line with regional energy regulations, notably as they relate to the planned South Stream gas pipeline.

Serbia and the EU begin formal discussion on accession in January. In a status report, the EU said the Serbian government has made progress in aligning itself with European governance, but it's lacking in key foreign policy and economic areas.

"Serbia needs to step up its efforts towards alignment with the EU acquis in particular in the fields of energy -- including on the South Stream gas pipeline," it said Wednesday.

Serbian Foreign Minister Ivica Dacic met with Russian officials in Moscow this week to discuss the natural gas pipeline Russia views as a means to diversify a gas transit network vulnerable to geopolitical concerns over Ukraine.

Ukraine hosts more than half of all Russian natural gas bound for European markets. With Europe concerned over not only the crisis in Ukraine, but also the role of state-controlled companies like Russia's Gazprom, Dacic said lingering questions over South Stream should "be settled between Russia and Brussels."

Gazprom in 2013 supplied Serbia with about 70 billion cubic feet of gas and said Wednesday the country should have adequate winter supplies. The company said it was waiting for the necessary permits to begin South Stream construction in Serbia.