ISLAMABAD, May 22 (Reuters) Pakistan, Iran and India vowed today to go ahead with a gigantic project to pipe Iranian natural gas to India through Pakistan despite U S opposition.

Energy officials of the three countries opened two days of talks to review progress on the 7 billion dollar pipeline project and ''expressed satisfaction over its pace.'' ''(They) reiterated the desire of their leadership to implement the project as soon as possible for their mutual benefit,'' said a statement issued by Pakistan's Petroleum Ministry after the talks which will conclude tomorrow.

The officials discussed financial, legal and technical aspects of the project as well as gas price and the route of the proposed pipeline, it added.

The three countries, which hope to sign a final deal in June, have been discussing the project over the last few years but progress has been slow because of hostility between Pakistan and India and more recently U S opposition to the project.

The United States is trying to discourage both Pakistan and India from doing business with Iran while Tehran remains under suspicion of trying to develop nuclear weapons.

Instead, Washington wants them to back another proposed gas pipeline, running from Turkmenistan, through Afghanistan.

Reuters DKS DB2327