Signaling a tough campaign, a top Bush administration official urged Congress on Wednesday to approve a landmark plan to share nuclear technology with India.

"India can be trusted," Undersecretary of State Nicholas Burns said.

Critics, including former Sen. Sam Nunn, D-Ga., are skeptical of the agreement reached March 2 by President Bush and Indian Prime Minister Manmohan Singh of India.

It requires Congress to exempt India from U.S. laws that restrict trade with countries, such as India, that have not submitted to full nuclear inspections.

Among concerns raised by Nunn, who played a leading role on military issues in Congress, were that the agreement would promote a regional arms race with China and Pakistan and make it more difficult for the United States to win support for sanctions against such countries as Iran and North Korea.

Burns said "we take his views very seriously." But, Burns said at a news conference, "we're far better off" having India submit to supervision under the agreement than having the country isolated.

He added that "India is a country that does not proliferate."

"We are going to make a convincing case," Burns said.

Legislation to implement the plan was introduced last week. Burns said Secretary of State Condoleezza Rice would testify in support of the measure.

Also, two assistant secretaries of state, Richard Boucher and Stephen Rademaker, were sent to Vienna to promote the plan with the Nuclear Suppliers Group, an assembly of 35 nations that export nuclear technology.

"India is accepting international verification," he said. "India is accepting international inspection. Who can argue with that?"

He said the agreement reflects "the emergence of a new global partnership between India and the United States."

Burns said it should cause no problem with Pakistan, traditionally a rival of India, and that the United States maintains good, although different, relations with Pakistan.

Pakistan on Tuesday successfully test-fired a cruise missile that can carry a nuclear warhead and hit targets within a 310-mile range, the army said.

Both Pakistan and India are nuclear-capable nations.