U.S. Defense Secretary Robert Gates is calling for the development of a new generation of American nuclear weapons to deter aggression by a variety of potential adversaries, including rogue states and terrorists. VOA's Al Pessin reports from the Pentagon.

Secretary Gates says the United States is the only declared nuclear power that does not have a nuclear weapons modernization program and the ability to build new nuclear warheads. He says U.S. allies France and Britain have such programs, as do two countries which he says are not U.S. adversaries, but whose nuclear modernization efforts can not be ignored.

"China and Russia have embarked on ambitious paths to design and field new weapons. To be blunt, there is absolutely no way we can maintain a credible deterrent and reduce the number of weapons in our stockpile without either resorting to testing our stockpile or pursuing a modernization program," he said.

Gates says China is expanding its nuclear arsenal, increasing the number of short-, medium- and long-range missiles it has, and the types of systems it has to deliver them. But he says there has been "a rudimentary start" to a U.S. strategic dialogue with China, which he hopes will build a foundation for future agreements to limit nuclear arms.

Secretary Gates says Russia is increasing its reliance on nuclear weapons, with new intercontinental ballistic missiles, sea-based systems and atomic weapons manufacturing facilities, partly because they are less expensive than maintaining large conventional forces.

He also expressed concern that some Russian nuclear weapons may have reached rogue states or terrorist organizations during the chaotic years following the fall of the Soviet Union.

The secretary says the aging U.S. nuclear force is becoming less reliable every year, with no new systems and no testing, while the stockpile is also shrinking under existing treaty requirements. He says the old systems are reaching the limits of their potential for technological upgrades. "We must take steps to transform from an aging Cold War nuclear weapons complex that is too large and too expensive, to a smaller, less costly but modern enterprise that can meet our nation's nuclear security needs for the future," he said.

Secretary Gates called on the U.S. Congress to resume funding of a program to develop a new American nuclear warhead that he says would not expand capabilities, but could make it easier for the United States to reduce the overall number of weapons in its atomic arsenal. "The program we propose is not about new capabilities - suitcase bombs or bunker busters or tactical nukes. It is about safety, security and reliability. It is about the future credibility of our nuclear deterrent and it deserves urgent attention," he said.

Gates says such a program would also revitalize U.S. nuclear science and related industries, which he says are in danger of being crippled by a lack of money and brainpower.

The defense secretary spoke at the Carnegie Endowment for International Peace in Washington, an organization devoted to promoting global cooperation. Gates said he chose the venue to speak about nuclear weapons because he believes deterrence is as important today as it was during the Cold War - helping convince a variety of countries and groups not to attack the United States or its allies, and limiting their ability to put pressure on their neighbors.