Ambassador Mohammad Ebrahim Taherian told Iran's semiofficial Fars News Agency there are rivals to a pipeline clouded by sanctions imposed on Iran's energy sector.
"Owing to the grave conditions of energy (supply and demand) in Pakistan, some of the country's major cities spend half of the day without electricity, meaning that Pakistan's need to energy is real and inevitable," he said Sunday.
Iran last year pulled out of a finance deal for Pakistan because of sanctions pressure.
Pakistan was slated to get 21 million cubic feet of natural gas per day from the Iranian pipeline.
The U.S. government supports a rival pipeline that would deliver natural gas to Pakistan from Turkmenistan. Last year, Washington said it was negotiating the terms of a $95 million loan to Pakistan to help it build a 50-megawatt wind power plant to help establish another layer of reliable electricity.