Pyongyang has conducted seven rounds of short-range missile tests since July with denuclearization talks with the U.S. in limbo.
Victor Cha was nominated to become Trump's ambassador to South Korea but was dropped after warning the White House against a pre-emptive strike on the North.
"It's not a stretch to say that Donald Trump's most lasting legacy may well be writing what he calls love letters to a dictator in North Korea," Joe Scarborough said.
Russia's weather agency data showed barium, strontium, and lanthanum isotopes were released from blast at Nyonoksa test site in the Arkhangelsk region.
The explosion killed at least five people and is believed to have involved a new nuclear-powered cruise missile.
The 21,000-ton Akademik Lomonosov is being sent to remote Siberian to provide power for local oil platforms.
Just as Russia's floating nuclear power unit began a journey toward Alaska, a radioactive missile accident shrouded in mystery raised more concerns about Moscow's record.
Radioactive pee is just one of the strange incidents cited in a new report from the Australian Radiation Protection and Nuclear Safety Agency.
Foreign Minister Javad Zarif gave an interview in New York City, where he is under tight visa restrictions, during a visit to the United Nations.
The RS-28 Sarmat is reportedly able to carry a nuclear payload capable of destroying an area the size of Texas.
"Russia probably is not adhering to its nuclear-testing moratorium," Lieutenant General Robert Ashley said.
President Donald Trump threatened "the official end of Iran" in a tweet days earlier.
"The prospect for resolving the nuclear issue will be much gloomier" without a U.S. pivot, a North Korean foreign ministry official said.
Trump won't get far unless he "moves away from maximalist demands and demonstrates that he can be a credible partner in diplomacy," said Arms Control Association's Kelsey Davenport.
"#WeHaveTheWatch," the North American Aerospace Defense Command (NORAD) tweeted.
China warned that a "certain major country has withdrawn from one international treaty and mechanism after another while building up its own nuclear and missile power."
Iranian Foreign Minister Mohammad Javad Zarif challenged President Donald Trump to "drain the swamp" of Washington war hawks like John Bolton.
Major General Hossein Salami, head of Iran's Revolutionary Guard, warned that his country was nearing "a full-scale confrontation with the enemy."
As The Century Foundation's Dina Esfandiary argued, however, "I don't think they're worried about not having international support."
Central Command said a U.K. coalition general's comments "run counter to the identified credible threats available to intelligence from U.S. and allies regarding Iranian backed forces in the region."
"That's what happens when you listen to the mustache," Iranian presidential adviser Hesameddin Ashena tweeted to Trump in an apparent reference to national security adviser John Bolton.
North Korean supreme leader Kim Jong Un said, "Genuine peace and security of the country are guaranteed only by the strong physical force capable of defending its sovereignty."
"By testing ballistic missiles this month, both the U.S. and North Korea risk blowing up the delicate progress that has been achieved to date through diplomacy," Rick Wayman of the Nuclear Age Peace Foundation said.
"Thus far what you've seen this president do is heap praise on Kim Jong Un and kind of revel in the spectacle of these summits, where nothing happens," said Ben Rhodes, former deputy national security adviser to Barack Obama.
Iran's top diplomat said his country would stop only "some" actions it has "voluntarily" carried out. But his counterpart in the U.S., which is no longer part of the deal, said Tehran's either in or out.
"War with Iran is playing with fire, and it will burn all, and not just Iran," said Iranian lawmaker Alaeddin Boroujerdi.
The White House said President Donald Trump and Russian President Vladimir Putin had a "very positive" conversation as tensions between their countries reached a historic high.