Addressing a joint press conference with Bush after an hour-long talks at the Hyderabad House here, Indian Prime Minister Manmohan Singh said "we have reached a mutually satisfactory understanding to carry forward the July 18 (last year) agreement signed by President Bush and me on nuclear cooperation".

Bush declared that "we have reached a historic agreement on nuclear technology cooperation" and made a dour three-point defence of the deal with India contending it was in the economic interest of US to help India develop nuclear power programmes.

The agreement envisages preparation of a plan to separate India's civilian nuclear facilities from military ones in return for US securing approval of the Congress and the 44-nation Nuclear Suppliers' Group (NSG) for supplying nuclear fuel and reactors to India.

That would end decades of nuclear isolation for India, which was placed under international sanctions after conducting nuclear tests in 1974 and 1998.

"That plan has been successfully completed," Singh said and added that President Bush would now have to obtain the approval of the US Congress and NSG and India will have to approach the International Atomic Energy Agency (IAEA) for India-specific inspection and safeguards of its civilian nuclear facilities.

Bush acknowledged that the deal was not easy either for him or the Indian prime minister but asserted "it is a necessary agreement which will help both the countries."

The deal, which would give India access to US nuclear technology to meet its soaring energy needs, has been opposed by some members of the US Congress because India has not signed the Nuclear Non-Proliferation Treaty.

Asked by a reporter how he will sell the deal to the US Congress, Bush replied "people in the United States must understand that trade with India is in our interest, diplomatic relationship with India is in our interest and cultural exchange is in our interest".

"Congress has got to understand that if India's nuclear power is allowed, it will create less dependence on fossil fuel, lead to less demand and help bring down the international oil price, which will help the American consumers," he said.

Thirdly, nuclear power is clean fuel and reprocessing of fuel is clean and it will help reduce pollution, the US president said adding "this deal is in our interest".

Without naming Iran or North Korea, Bush took the opportunity to send out a clear message by saying that India has charted a way forward which was an opportunity for others to follow to benefit from civilian and peaceful nuclear power programme.

Answering a question from an American journalist about US nuclear non-proliferation lobby's concerns over the nuclear deal with India, Bush made a veiled criticism on non-proliferation hawks and said "some people just don't change and don't want to change."

"Things change and leaderships make the difference. I am trying to think differently. This deal is in our interest. This will help both the countries to grow", Bush said adding "the relationship between the two countries is changing for the better".

Manmohan Singh said President Bush is admitted for his strong stand against terrorism and "we have agreed on the need to root out terrorism".

He said the two sides identified a number of areas and initiatives for cooperation including energy, science and technology, agriculture and investment.

"There are no limits to Indo-US cooperation," he added.

Bush said India and US had built their strategic partnership based on common values and both were promoting democracy globally.

He pointed out both the countries have suffered from terrorist attacks on their home soil.