Obama: Urgent Nuclear Threats Require International Cooperation

A day after the close of the Group of 20 nations summit, U.S. President Barack Obama is stressing international cooperation in countering nuclear proliferation.

In his weekly radio and Internet address, the president said the United States is "committed to a new chapter of international cooperation."

He said the U.S. is pursuing an agreement with Russia to reduce weapons arsenals, and he said other nations, like Iran and North Korea, must also meet international responsibilities.

President Obama said the U.S. will continue to "stand with our allies and partners" to push North Korea to stop developing weapons of mass destruction.

Reiterating accusations he made alongside the leaders of France and Britain at the G20 summit, Mr. Obama said Iran is building a secret uranium-enrichment plant, which he said is part of "a disturbing pattern of Iranian evasion."

He said the new plant adds urgency to international talks with Iran scheduled for October 1.