Zardari met last week with Iranian officials to discuss a natural gas pipeline planned from the South Pars field in the Persian Gulf. Iran states it has already constructed some sections of the $75 billion project and offered Pakistan financial assistance for it to do the same.
The Pakistani president told reporters after returning from meetings last week in Iran the pipeline could go ahead despite the reservations from the United States.
"Nobody has the power to halt this project," he was quoted by The Express Tribune newspaper in Pakistan as saying.
Last week, U.S. State Department spokesman Patrick Ventrell said Pakistan should find other ways to address its energy needs. He said it was in Pakistan's best interest to avoid taking action that may violate existing sanctions that target Iran's energy sector.
"We recognize that Pakistan has significant energy requirements but we really think there are other long-term solutions to Pakistan's energy needs," he said.