(CNN) -- U.S. President George W. Bush is en route to India Wednesday to begin a five-day South Asian visit designed to strengthen alliances in the region.

The U.S. leader also is hoping to sign a critical nuclear accord with New Delhi, a move which is raising political hackles in both nations.

Also on the agenda for the Bush visit to South Asia this week are security and economic ties between India and the United States, and India's relations with neighboring Pakistan, also a nation with a nuclear capability.

Pakistan is a key U.S. ally in the war on terror, but many in Washington want to see Islamabad make stronger efforts to dismantle terrorist training camps on its soil.

Under the proposed nuclear deal between New Delhi and Washington, the United States would supply nuclear technology and fuel desperately needed by India to fuel its booming but energy-starved economy.

India has pledged in return to separate its military and civilian nuclear programs and open up the civilian ones to international inspection.

But some members of the U.S. Congress, who must approve the deal, believe this deal will undermine the international Nuclear Nonproliferation Treaty, which India has refused to sign.

On the other side, some Indian scientists and nuclear industry supporters say the pact will erode their nation's military ambitions.

Indian Prime Minister Dr. Manmohan Singh is eager to ease these fears.

"There has been no erosion of the integrity of our nuclear doctrine either in terms of current or future capabilities," Singh said recently.

Despite the potential political fallout, there is a lot to gain for both sides from such a deal going ahead.

"The essence of this strategic partnership is to provide a countervailing influence to China ... to act as a restraint on the exercise of Chinese power," security analyst Brahma Chellaney told CNN.

There is an economic incentive for Washington, as well. A more buoyant Indian economy fueled by U.S. civilian nuclear technology could be good news for U.S. manufacturers eager to sell into India's billion-strong marketplace.

Given weeks of hectic discussions between U.S. and Indian diplomats and the huge stakes involved for both countries, President Bush is warning negotiations on a final nuclear deal will go down to the wire.

`This is not an easy decision for India nor is it an easy decision for the United States, and implementing this agreement will take time and it will take patience from both our countries," Bush said in an interview.

Speaking on Air Force One while traveling to India, U.S. Secretary of State Condoleezza Rice said some sticking points for the deal remained.

"The one thing that is absolutely necessary is that any agreement would assure that once India has decided to put a reactor under safeguard that it remain permanently under safeguard," she said in a report from The Associated Press.

That would prevent India from transferring a reactor from civilian to military status and exempting it from international inspections.

Rice said she was uncertain whether there would be an agreement during Bush's trip but said the success or failure of his visit would not be determined by that.

"We're still working on it," she said. "Obviously it would be an important breakthrough" for the United States and India.