President Obama said Tuesday that the Department of Defense's Nuclear Posture Review recognizes that "the greatest threat to U.S. and global security is no longer a nuclear exchange between nations, but nuclear terrorism by violent extremists and nuclear proliferation to an increasing number of states."

The release of the NPR comes just days before the President is expected to meet with Russia's Dmitry Medvedev in Prague, where the two leaders will sign a new START treaty that cuts the number of both countries' warheads and missiles. The report also precedes next week's Nuclear Security Summit hosted by President Obama in Washington.

Mr. Obama reaffirmed America's commitment to preventing nuclear proliferation and nuclear terrorism, saying that his administration has increased funding for programs to stop the spread of nuclear weapons. To encourage other nations to meet their obligations under the Nuclear Non-Proliferation Treaty, the President announced that the U.S. will not "use or threaten to use nuclear weapons against non-nuclear weapons states," according to a statement released by the White House. In addition, Mr. Obama pledged not to conduct nuclear testing or develop warheads. He warned that nations who fail to meet their obligations will become more isolated from the international community, inevitably making themselves less secure.

Despite the limitations Mr. Obama put on future nuclear development, he emphasized that the U.S. will remain secure, with an "effective arsenal that guarantees the defense of the United States, reassures allies and partners, and deters potential adversaries." He described the measures announced as part of the new strategy as an advancement in American national security.