UNITED NATIONS - United Nations Secretary-General Antonio Guterres opened his first General Assembly gathering Tuesday, warning that North Korea's nuclear ambitions are the world's most serious challenge.
"Today proliferation is creating unimaginable danger, and disarmament is paralyzed," Guterres said in New York.
"Millions of people live under a shadow of dread cast by the provocative nuclear and missile tests of the Democratic People's Republic of Korea," the secretary-general said, referring to North Korea by its formal name. "I condemn those tests unequivocally."
Guterres commended the unity of the U.N. Security Council in its recent tightening and imposing of economic sanctions on Pyongyang, saying the move sends "a clear message" to the leadership there.
"Fiery talk can lead to fatal misunderstandings," he warned. "The solution must be political — this is a time for statesmanship — we must not sleepwalk our way into war."
Less than an hour later, U.S. President Donald Trump took the podium to deliver his first U.N. address and warned North Korea that if the United States is forced to defend itself or its allies the U.S. would have "no choice but to totally destroy North Korea."
"Rocket man is on a suicide mission for himself and for his regime," Trump said, using his recently coined nickname for Kim Jong Un. "The United States is ready, willing and able, but hopefully this will not be necessary."
In his UNGA speech, Nigeria's President Muhammadu Buhari proposed that the U.N. Security Council send a delegation to Pyongyang to engage the North Korean leader.
"The crisis in the Korean peninsula underscores the urgency for all member states, guided by the spirit of enthroning a safer and more peaceful world, to ratify without delay the treaty prohibiting nuclear weapons," he said. That treaty will be open for signatures at the United Nations starting Wednesday morning.
U.N. chief Guterres, who took office January 1, outlined several other threats and challenges facing the world and urged multilateral solutions.
"We are a world in pieces," Guterres told world leaders. "We need to be a world at peace."
Of the numerous entrenched conflicts in the Middle East, Africa and South Asia, he said "no one is winning," and the most vulnerable in society are paying the highest price as combatants "thirst for outright military victory, at any cost."
On terrorism, the secretary-general said there is no cause or grievance that justifies such actions, but cautioned against heavy-handed approaches in dealing with it, saying they are counterproductive.
"As soon as we believe that violations of human rights and democratic freedoms are necessary to win the fight, we have lost the war," he cautioned.
During his UNGA address, Afghan President Ashraf Ghani said there are more than 20 international terrorist groups that have a presence in his country.
"The future of Afghanistan matters, because we are on the front line of the global effort to eradicate terrorism," he told the assembly.
Guterres, whose primary pillar is the prevention of conflict, called out the growing humanitarian crisis in Myanmar that has sent more than 400,000 Rohingya Muslims fleeing to neighboring Bangladesh in the past month. He recently referred to the military's abuses as ethnic cleansing.
On Tuesday, the secretary-general acknowledged a speech in Myanmar earlier in the day by de facto civilian leader Aung San Suu Kyi.
"But let me emphasize again: The authorities in Myanmar must end the military operations and allow unhindered humanitarian access," Guterres said. "They must also address the grievances of the Rohingya, whose status has been left unresolved for far too long."
The plight of the Rohingya minority was a common theme among leaders addressing UNGA Tuesday. Turkish President Recep Tayyip Erdogan, whose phone call with Aung San Suu Kyi this month marked her first public comments on the situation, called the crisis "almost ethnic cleansing."
"The international community has not given a good account of itself regarding the humanitarian plight which Rohingya Muslims have been exposed to," Erdogan said. "If this tragedy in Myanmar is not stopped, the history of humanity will face the embarrassment of another dark state."
Nigeria's Buhari cautioned that the Myanmar crisis is "very reminiscent of what happened in Bosnia in 1995 and in Rwanda in 1994," referring to the Srebrenica massacre and the Rwandan genocide.
Iran nuclear deal
Another issue that took center stage Tuesday at the UNGA was the Iran nuclear agreement.
President Trump declared the 2015 deal to prevent Iran from getting a nuclear bomb "an embarrassment," and "one of the worst and most one-sided transactions" the U.S. ever entered into. He suggested he may pull U.S. support for it.
Israeli Prime Minister Benjamin Netanyahu said the agreement would not stop Iran from getting atomic weapons.
"That's why Israel's policy regarding the nuclear deal with Iran is very simple: Change it or cancel it, fix it or nix it," Netanyahu told the General Assembly. "Nixing the deal means restoring massive pressure on Iran, including crippling sanctions, until Iran fully dismantles its nuclear weapons capability."
The Israeli leader also had a tough message for Iran's leaders.
"Those who threaten us with annihilation put themselves in mortal peril," he warned. "Israel will defend itself with the full force of our arms and the full power of our convictions."
During Tuesday's speech, the U.N. chief also spoke of the importance of mitigating the impact of climate change and urged governments to implement the Paris climate accord.
"It is high time to get off the path of suicidal emissions," Guterres said. "We know enough today to act — the science is unassailable."
French President Emmanuel Macron spoke extensively on the issue, linking it to a number of natural disasters around the world in recent months, and echoing Guterres' call to nations to move forward on the Paris agreement.
"That agreement is not up for renegotiation; it binds us, it rallies us together. Taking it apart would mean taking apart a pact that exists not just between states but between generations. It can be improved, we can have new contributions, new input, but we will not backtrack," Macron said Tuesday.
Leaders will address the Assembly all week. Speakers Wednesday include British Prime Minister Theresa May, Iranian President Hassan Rouhani, Japanese Prime Minister Shinzo Abe and Myanmar's second vice president, U Henry Van Thio.
VOA's Peter Heinlein contributed to this report.