The United States is broadening its military relationship with India in a signigicant way; there have been arms deals totaling almost $250 million between the two countries over the last several months.

Carter administration officials said they are encouraged by this resumption in the relationship after a 15-year suspension but stressed the Soviet Union is still India's main arms supplier and will remain so for the foreseeable future.

"India just wants to make sure it has a second source," said one official involved. Even so, the entree puts the administration in a better position to influence events in that part of the world, officials contend.

Asked if resuming sales to India without doing the same thing with Pakistan represented a tilt toward India, one administration official responded that it has been Pakistan's choice to buy its arms elsewhere, with China a big supplier.

Pentagon officials said the last unclassified sale of arms to Pakistan was in 1978 when the Pakistanis bought 40 Navy Mark 46 torpedoes. India's previous arms purchases from the United States date back to the mid-1960s, the Pentagon said.

The breakthrough in arms sales to India came in June when New Delhi agreed to buy $39 million in TOW antitank missiles and associated equipment. aThe order included 60 launchers and 3,724 missiles, which are guided to their targets by radio commands sent through wires streaming out from the missile as it flies along.

Last month, India signed up to buy 29,000 155mm shells for $78.7 million and 230 M198 155mm howitzers or $111 million. The deal will not become final until Congress has more time to review it, but administration officials said they have heard of no objections.

The total order of $228.7 million for the year to date is expected to end up at a higher price, Pentagon officials said, probably around $250 million because of adjustments in process.