"Now, if you look at the current situation and developments on the Korean peninsula, the United States did not hesitate to escalate, aggravate, increase its threats and blackmails with increased hostilities toward the DPRK," he said, using the initials of the country's official name, the Democratic People's Republic of Korea.
"And the situation on the peninsula is on the brink of explosion, and nobody knows when the war will break out," Ri warned.
Under this situation, he said, six-party talks on the North's nuclear disarmament, which Pyongyang walked away from in 2009, have come "to the point of becoming almost a dead body at the moment." The talks include the U.S., China, Japan, Russia, North and South Korea.
Ri said North Korea is a full-fledged nuclear weapon state and should be treated the same way as other nuclear weapon states like the United States whose activities are not investigated by the IAEA.
IAEA inspectors were most recently expelled three years ago after the North quit the six-party talks. North Korea restarted its nuclear facilities and less than a month later, in May 2009, it conducted its second nuclear weapons test.
Amano also urged the Syrian government to respond to questions about a building destroyed by Israeli warplanes at the Deir El-zour site in the Syrian desert in 2007. The IAEA has said the building was "very likely" the covert site of a nuclear reactor.
The United States asserted more than four years ago that the bombed target was a nuclear reactor, but Syria has repeatedly denied allegations of any covert nuclear activity or interest in developing nuclear arms, saying the building was a non-nuclear military site.
Amano also reported on prospects for convening a conference in 2012 on the establishment of a Middle East zone free of nuclear weapons, which the 189 nations that are parties to the NPT called for in May 2010.
The IAEA held a forum on the possible relevance of creating such a zone in November 2011, he said, but "there remain fundamental differences of views among countries of the region on this important issue and it has not been possible to make further progress."
Egypt's U.N. Ambassador Mootaz Ahmadein Khalil stressed the importance of holding the conference in 2012 and told the General Assembly that any delay "will affect the effectiveness of verification activities in the Middle East" and "the integrity of international efforts to prevent nuclear proliferation."
He warned that it could even lead to the failure of the next conference to review the NPT in 2015.
Israel is not a party to the NPT and has long said a full Arab-Israeli peace must precede such weapons bans.
Thomas Mayr-Harting, head of the European Union delegation to the United Nations, said it is holding a seminar in Brussels on Monday and Tuesday where "an open exchange of views on all aspects related to the creation" of a nuclear weapons-free zone in the Mideast will take place.