Iran said the ‘door was open’ for India to join the ambitious Iran-Pakistan-India gas pipeline but indicated that it could not wait indefinitely and the structure of the project could change in the future.

Iran has in place a bilateral arrangement with Pakistan on the gas pipeline and both the countries have begun work on the project, Iranian Foreign Minister Manouchehr Mottaki said.

"We have a bilateral arrangement with Pakistan and the door is open for our Indian friends. That (IPI) will be a reality...but I am not sure about the future," he said in an interaction at the Indian Council of World Affairs.

Mottaki claimed that more than 100 km of the pipeline has already been laid on the Iranian side and the Pakistani side has also "started action" on its side of the border.

"But when you consider this pipeline bilaterally, there is a definite capacity. If we make commitments with other partners, with other pipelines, to other regions, in such a case may be in the future the structure of the project may change. I do hope to have Indian participation as soon as possible," he said.

Mottaki said the issue was discussed during his interactions with Prime Minister Manmohan Singh and External Affairs Minister S M Krishna yesterday.

"During our negotiations, there were some questions and concerns and they needed some more consideration on this project," he said.