Humans abandoned the area in 1986, following what is generally regarded as the worst nuclear disaster in history.
Iran successfully tested the Hoveizeh cruise missile and have mounted precision warheads to the Khorramshahr 2 ballistic missile.
President Donald Trump said the U.S. "will work with NATO and our other allies and partners to deny Russia any military advantage from its unlawful conduct."
Trump is tearing up an actually functioning treaty that has reduced the threat of global nuclear war. His record on North Korea does not bode well for whatever he is hoping to put in its place.
Russia's deputy foreign minister said that "there are less and less people in Washington now who are ready to consider arms control as an effective way of ensuring their own security."
Russia defended its new 9M729 cruise missile, claiming it fell short of the range restricted by the 1987 Intermediate-range Nuclear Forces treaty that the U.S. is threatening to leave.
Trump and Secretary of State Mike Pompeo met Friday with Kim Yong Chol, vice chairman for the central committee of the ruling Korean Workers' Party.
New satellite images show Iskander ballistic missile units conducting drills within range of the border.
"If you liked the president's border wall, wait until you see his space wall," arms control expert Joseph Cirincione said.
Plasma—which reaches temperatures of hundreds of millions of degrees—is unstable, making it difficult to control.
The 3M-54 Kalibr cruise missile is already capable of delivering a blow more than 1,200 miles away, and the new and improved version may reach the western Atlantic.
New York Times story details Trump's process of showing off his "beautiful letters" from North Korea's supreme leader.
Orphans of the bomb share their stories 75 years on.
The Tupolev Tu-22M3M supersonic long-range strategic bomber reportedly flew for 37 minutes and reached an altitude of over 4,920 feet.
Russian President Vladimir Putin said that the successful Avangard hypersonic glide vehicle test "is a wonderful, great gift to the country for the New Year!"
A defense source told Russian state media that "the underwater trials of the nuclear propulsion unit of the Poseidon drone are underway."
Russian Foreign Minister Sergey Lavrov said that "there is no doubt that there can be no winners in a nuclear war and it should never be unleashed."
While North Korean supreme leader Kim Jong Un has followed a "very clear" strategy, President Donald Trump is a "wild card," experts said.
Pyongyang said the U.S. needs to "study geography" and realize denuclearization refers to the entire Korean Peninsula.
Iran's top diplomat criticized Israeli Prime Minister Benjamin Netanyahu for bragging about "offensive missiles" that "can reach anywhere."
Over 18,000 exercises and training sessions were conducted in the past year and new ones are being planned for 2019, Russia's defense minister said.
Iran's envoy to the U.N. accused the U.S. secretary of state of "fabrication, disinformation and evoking irrelevant criteria."
Secretary of State Mike Pompeo blasted Russia's decision to send nuclear-capable warplanes to Venezuela, while the Kremlin called the U.S. diplomat's remarks "completely inappropriate."
The Department of Energy plans to relabel radioactive waste to the level of shared by contaminated protective clothing, rags and medical equipment.