New Delhi: The verbal duel between India and Iran on Farzad B gas field has intensified with Tehran claiming that it is under no obligation to award the contract to India.

Iran`s rebuff has taken the Indian side by surprise as the country wants to invest as much as $11 billion to develop Iran's Farzad B gas field.

Tehran now says that Iran has also made light of India's threat to import less crude oil from it, with its Parliament Energy Commission chief saying Iran could find other customers for its oil.

In May, Iran signed a basic agreement with Russia's Gazprom for development of the gas field which was discovered by a consortium of Indian state-run companies. This was seen as a retaliation against what Iran saw as a threat from India to cut purchase of Iranian oil if the commercial contract for Farzad B didn't happen.

India officially said last month that it wants Tehran to reciprocate the faith shown by New Delhi in it as reflected in India's decision to buy substantial crude from Iran even when it faced international sanctions.

This was followed by a fresh offer earlier this month to invest $11 billion for development of the gas field.

Iranian lawmaker and spokesperson of Iran's Majlis Energy Commission Asadollah Gharekhani said last week that while India had been allowed to conduct technical surveys on Farzad B, giving India development rights was never a part of any agreement.

"In the past, it was decided that Iran and India jointly carry out (feasibility) studies on the Farzad B oil field. The studies have been conducted and have finished. 

"Under equal circumstances, this company (Indian consortium) could take priority. However, if there is a difference between the Indian company and other firms in terms of technology, technical knowhow and investment, Iran will, based on the independence and freedom that is has, choose the company which would best serve the country's national interests," he added.