Iran on Tuesday gave India a four-month deadline to formally agree its participation in a multi-billion dollar project to transport Iranian gas to India via Pakistan.
The warning came after Iran and Pakistan on Saturday finalised the content of the $7.4-billion gas export deal, originally a tripartite project, which is scheduled to be signed within a month.
"I don't think we would wait for them (Indians) more than three or four months," the managing director of National Iranian Gas Exports Company, Nosratollah Seifi, told reporters.
Seifi however expressed hope that New Delhi would still join the much-delayed project, under which energy-poor India would receive 30 million cubic metres per day of Iranian gas.
"I think India will join the gas exports project because of its extreme and immediate need for energy," he said.
Seifi said the delay by India, an increasingly important US ally, was due to both energy and political issues.
"They have domestic issues and we understand this. They think about whether to use nuclear energy... There are also foreign pressures."
Talks on the project to supply gas to India via Pakistan and Pakistan itself through a 2,600-kilometre pipeline began in 1994 but were stalled by tensions between India and Pakistan.
An early October agreement between Iran and Pakistan marked a breakthrough in the talks when they agreed to a periodic revision of gas prices every three years instead of a long-term fixed price.