Britain

British Prime Minister Gordon Brown did not attend the Nuclear Security Summit because he was campaigning for British parliamentary elections on May 6. Instead, Foreign Secretary David Miliband represented London with Brown's full authority.

Miliband praised Obama's vision and leadership in establishing a "gold standard of what nuclear security means." In his remarks at the conference, he stressed the importance of protecting nuclear-related information. "We must keep the science, as well as the substance of nuclear materials, out of terrorist hands," he said.

France

French President Nicolas Sarkozy told CBS News hours before the opening of the Nuclear Security Summit that he could not abandon his nation's nuclear weapons program "on a unilateral basis, in a world as dangerous as the one in which we live today."

"I have inherited the legacy of the efforts made by my predecessors to build up France as a nuclear power," he said. "And I could not give up nuclear weapons if I wasn't sure the world was a stable and safe place."

Citing the need to avoid jeopardizing "the security and safety" of his country, Sarkozy also hinted that the United States and Russia should take the lead in reducing their own huge nuclear stockpiles, rather than expecting France, which has a much smaller stockpile of atomic weapons, to disarm.

India

Indian Prime Minister Manmohan Singh said after the Nuclear Security Summit that nuclear security is a crucial issue for India since "without ensuring security we will not be able to harness nuclear energy for our developmental purposes."

"The world is beginning to see merit in pursuing universal, non-discriminatory and complete nuclear disarmament," said Singh, adding India would continue to persevere in this direction.

Pakistan

Pakistani Prime Minister Syed Yousaf Raza Gilani made a commitment at the Nuclear Security Summit to increasing port security and preventing smuggling of nuclear materials. He said Pakistan has implemented multi-tiered mechanisms and processes to ensure the security of nuclear materials and facilities.

Gilani and Foreign Minister Shah Mahmood Qureshi both dismissed security fears surrounding Pakistan's nuclear stockpiles, saying Pakistan had taken "effective steps for nuclear safety, security and non-proliferation through extensive legislative, regulatory and administrative frameworks."

(Reporting by Chen Wen from Washington, D.C.)

Nuclear Non-proliferation Treaty

To prevent the spread of nuclear weapons, the Treaty on the Non-Proliferation of Nuclear Weapons, also known as the Nuclear Non-proliferation Treaty (NPT), was signed in July 1968 and entered into force on March 5, 1970. The NPT officially recognized five countries as "nuclear weapon states"--the United States, Russia, the UK, France and China. The more than 180 non-nuclear weapon states that are parties to the NPT, on the other hand, have pledged not to develop or otherwise acquire nuclear weapons.

Today, in addition to the five official nuclear powers, three countries that are not parties to the NPT—India, Israel, and Pakistan—are known to possess nuclear weapons. North Korea, a party to the NPT until officially withdrawing in 2003, has openly conducted at least one nuclear weapon test.

Iran, another signatory of the NPT, meanwhile, claims its nuclear program is devoted solely to civilian nuclear power and research purposes.

Nuclear Smuggling Incidents

March 1993: Nearly 3 kg of enriched uranium-238, with a purity of 90 percent, was stolen in St. Petersburg, Russia.

August 1994: German police seized about 360 grams of Russian-made plutonium in Munich.

December 1994: A total of 2.7 kg of enriched uranium-235, with a purity of 80 percent, was reportedly stolen from a nuclear research center in Obninsk, Russia.

The end of 1998: Russian officials announced they had disrupted an attempt to steal 18.5 kg of high-enriched uranium from a military factory in Chelyabinsk region.

January 2001: Greek police came across a number of metallic plates buried in a forest. Criminals, they later discovered, were planning to sell the plates, which contained 3 grams of plutonium, for a profit.

2001: Turkey announced that it had uncovered a nuclear smuggling deal with the sale of 1 kg of enriched uranium, worth $750,000, to an undercover police officer.

(Source: Guangming Daily)