Iranian state-funded broadcaster Press TV aired coverage of a border ceremony marking the inauguration of a $7.5 billion natural gas pipeline planned from Iran. Press TV noted that ministers from regional neighbors attended the ceremony.
The project has faced a series of delays since it was proposed in the 1990s. India was once considered a partner in a project strongly opposed by the United States.
Farhatullah Babar, a spokesman for Zardari, told Pakistani newspaper Dawn that Islamabad was moving ahead with its energy interests in mind.
"The government is going to initiate this important project in view of the energy requirements," he was quoted as saying. "The project will bring economic prosperity, provide better opportunities to the people and help defeat militancy."
Iran said it has completed its section of the pipeline and agreed to provide Islamabad with a $500 million loan to finance construction on its side of the border.
Washington supports a rival pipeline planned from Turkmenistan, which has the support of the Asian Development Bank. Last week, U.S. State Department spokeswoman Victoria Nuland said the Iran-Pakistan pipeline raises "serious concerns" about potentially sanctionable activity.