In a glow of bonhomie, U.S. President Barack Obama and Indian Prime Minister Narendra Modi unveiled a deal aimed at unlocking billions of dollars in nuclear trade, a step that both sides hope will help establish an enduring strategic partnership.

The two countries reached an understanding on two issues that, despite a groundbreaking 2006 agreement, had stopped U.S. companies from setting up reactors in India and became one of the major irritants in bilateral ties.

"We are committed to moving towards full implementation," Obama told a joint news conference with Modi after he arrived in the Indian capital in a state visit. "This is an important step that shows how we can work together to elevate our relationship."