WASHINGTON Stating that the way India and Pakistan pursued atomic weapons has upset the balance of nuclear deterrence, Secretary of State Hillary Clinton said Friday that the US was working hard with both countries to try to limit the number of nuclear weapons. (W)ere working with both countries very hard to try to make sure that their nuclear stockpiles are ... well tended to, and that they participate with us in trying to limit the number of nuclear weapons, she said in a speech on nuclear non-proliferation at the University of Louisville, Kentucky. And both of them will be in Washington next week, she told university students. Pakistan Prime Minister Yousaf Raza Gilani and his Indian counterpart Manmohan Singh are participating in next weeks Nuclear security conference, which will be attended by 46 heads of state/government from around the world. The Summit, an initiative of President Barrack Obama, will focus on dangers posed by clandestine proliferation and illicit trafficking of nuclear material and the possibility of terrorists acquiring atomic material. There are three pillars to the Nuclear Non-Proliferation Treaty. One is disarmament, one is nonproliferation, and one is the peaceful use of nuclear weapons, the peaceful use of nuclear energy for civil nuclear purposes, Mrs. Clinton said. So the United States will continue to demonstrate its willingness, in concert with Russia, because we have so many more weapons than any of the other countries-you know, by a very, very big margin, she said in her speech on 'No Greater Danger: Protecting our nation and allies from nuclear terrorism and nuclear proliferation. Other countries that have pursued nuclear weapons-like India and Pakistan, for example-have done so in a way that has upset the balance of nuclear deterrence, the top US diplomat added. Mrs. Clinton said as long as there are nuclear weapons in the world, the United States will have those arms. We will not unilaterally disarm. We will maintain our nuclear deterrent, she declared. We will invest, not in new weapons, but in ensuring that the weapons we have are as effective as they would need to be in order for our deterrent to be credible. And the countries that we know that have actively pursued nuclear weapons that are still doing so today - North Korea, which we know has somewhere between one and six nuclear weapons, and Iran - and thats why were emphasizing so much international efforts against both of them to try to denuclearize the Korean Peninsula and prevent Iran from getting nuclear weapons in the first place.