The UN Security Council, in a Summit Declaration of 31 January, states that “the proliferation of all weapons of mass destruction constitutes a threat to international peace and security.” It specifically underscores the “integral role” of fully effective IAEA safeguards and the Council's resolve to take “appropriate measures” in case of any violation brought to its attention by the IAEA. Russian President Yeltsin announces major arms reductions; states that Russian Federation has control of nuclear weapons (strategic A-bombs are also located in Ukraine, Kazakhstan, Belarus). IAEA proposes assistance in verification of nuclear materials from dismantled nuclear weapons in former USSR. In February, the IAEA Board considers various measures, and adopts several, for strengthening the Agency's safeguards system.  The Democratic People’s Republic of Korea (DPRK, North Korea) signs NPT-safeguards agreement with the IAEA, which enters into force in April 1992. IAEA inspections begin in the DPRK in May 1992. The UN Conference on Environment and Development — the “Earth Summit” — in Rio de Janeiro, Brazil, in June adopts Agenda 21, a document calling for action to ensure the world's sustainable development. The IAEA is made the focal point for issues related to nuclear waste.