The unresolved issues include a transit fee Pakistan would charge and Iran's last-minute insistence on including a clause that the price of the gas would be reviewed after every three years.

It is expected that the issue of transit fee would be resolved at the ministerial-level talks in next two months.

However, officials of the three countries said they have moved forward in negotiating the cross-country gas project that proposes to wheel gas from Iran to Pakistan and India.

Iranian petroleum minister's special representative H Ghanimi Fard conveyed to Indian Oil Minister Murli Deora that Teheran invited Indian Prime Minister Manmohan Singh and Pakistan President Pervez Musharraf for signing an agreement for establishing the overland pipeline connecting the three countries.

However, sources said India would not be hustled into signing the agreement especially when gas availability is expected to improve significantly during 2007 and 2011. In any case, the gas from Iran cannot flow into India before 2011, going by the most optimistic assessment of the project.

Deora will meet his Pakistani counterpart in July-August to iron issues between India and Pakistan before the heads of the three governments sign the agreement.