"We will adhere to our commitments made," Rouhani said at an event in New Delhi.
"After signing a contract, haggling with it is ridiculous."
Under the agreement signed with the United States, Britain, France, Germany, Russia and China, Iran agreed to limit its nuclear activities in return for the lifting of many sanctions.
"If the U.S. violates this agreement... you will see that America will regret this decision," he said adding his country had always adhered to contracts deals so long as other party did not violate the contract.
Rouhani arrived in India on a three-day visit part of efforts to expand bilateral ties and cooperation in economic development.
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