South Korea is on heightened alert Friday amid growing tensions with North Korea, while Russian officials are pushing back against reports that Moscow is moving troops to Russia's border with the reclusive country.
Concerns are growing among the U.S., South Korea and their allies that the North is preparing for another nuclear test. Pyongyang attempted to test fire a missile on Sunday, but that operation failed and the missile exploded almost immediately after being launched.
Tuesday is the 85th anniversary of the founding of North Korea's army, seen as a likely occasion for a nuclear test.
The developments come amid heightened tensions between the U.S. and North Korea. Earlier this month, the U.S. said it was moving a Navy strike group into the west Pacific toward the Korean Peninsula in response to growing concerns over Pyongyang's weapons program.
North Korea dubbed the move an act of aggression, threatening a nuclear strike if provoked and warning that it was capable of quickly striking U.S. military installations in South Korea.
The Trump administration has taken an increasingly hard-line stance on North Korea, floating the possibility of a military solution to the tensions.
Reports this week suggested that Russia was moving military hardware and troops to its border with North Korea in anticipation of a U.S. attack.
But Russian officials denied that the movements were due to growing animosity between the U.S. and North Korea or concerns about the North's nuclear program and said that it was part of "scheduled maneuvers," The Associated Press reported.