"The gas pipeline is a bilateral issue between Pakistan and Iran," Foreign Ministry spokeswoman Tasnim Aslam said during a Thursday news briefing.
Pakistan says a pipeline from Iran could help offset an energy shortage brought on by aging infrastructure and a crumbling energy sector.
Envisioned more than a decade ago as a pipeline that could reach to India, the project has come up against pressure from Western powers concerned about its benefits to Iran.
Aslam said the development was plagued more by the lack of funding than by pressure from any foreign government.
"The progress on pipeline has been slow because of the funding issues and not because of the United States," she said.
Pakistan could get 21 million cubic feet of natural gas per day from the Iranian pipeline.
Iran says it's made progress on its end of the project but balked on a $500 million commitment to help Pakistan build the pipeline on its side of the border, citing economic sanctions related to its nuclear power program as a possible inhibitor.