The escalation of tensions between the U.S. and North Korea comes amid the new assessment by U.S. intelligence agencies that North Korea has the capability of fitting a miniaturized nuclear warhead inside an intercontinental ballistic missile.
In the wake of newly issued sanctions by the United Nations, North Korea warned that it would take "thousands-fold" revenge against the U.S., leading to President Donald Trump to vow that North Korea "will be met with fire and fury."
Here's what you need to know about the situation.
What missile capability does North Korea have?
Most of North Korea's military equipment dates back to the Cold War-era and was obtained from the Soviet Union and China. But the large size of its military poses a constant threat to South Korea, since 70 percent of its ground forces and half of its air and naval forces are stationed within 60 miles of the Demilitarized Zone that divides North Korea and South Korea.
North Korea has been working for the last decade to develop a nuclear weapons program and long-range ballistic missile program.
The product of that work was revealed in a July intercontinental ballistic missile test. At the time, the country's ability to put a miniaturized nuclear warhead was unclear, but it was the distance the ICBM traveled -- more than 3,400 miles -- that prompted concerns.
"This is the first time, if the analysis is correct, that we're seeing a North Korean weapon that can hit the United States. Not the mainland, but Alaska is very much part of the United States, and this is a very worrying development," Steve Ganyard, a retired Marine Corps colonel, said on "Good Morning America" on July 5, one day after the first North Korean ICBM test.
How far can the missiles travel?
North Korea has been firing these missiles vertically to maximize their distance and to avoid flying over Japan and other countries in the region.
"The missile itself reached an apex of almost 1,700 miles, which means -- had it been on a max-range trajectory -- it could have reached Anchorage and wouldn't have been far from reaching Seattle," Ganyard said on July 4 on ABC News' "World News Tonight."
The country conducted a second ICBM test on July 28. That missile, which traveled 621 miles laterally and was airborne for 45 minutes, was the longest flight of a ballistic missile in North Korea's history, according to the Pentagon.
Does North Korea have nuclear weapons?
Yes. North Korea has a small arsenal of nuclear weapons as proven by its five nuclear tests. The new assessment from the Defense Intelligence Agency estimates that North Korea now has as many as 60 nuclear warheads, much higher than previously believed. A 2016 Congressional Research Service report estimated that North Korea has between 44 and 66 pounds of separated plutonium, enough for at least half a dozen nuclear weapons. But other estimates are higher. The Institute for Science and International Security estimated in 2014 that North Korea could build 10 to 16 nuclear weapons.
How advanced are North Korea's missiles?
On Aug. 8, it was revealed that members of the U.S. intelligence community believe North Korea's nuclear capabilities are more advanced and the country may have developed the technology to place a miniaturized nuclear warhead inside a missile, a U.S. official confirmed to ABC News.
The Washington Post first reported the news. A U.S. official later confirmed the details to ABC News.
"The IC [intelligence community] assesses North Korea has produced nuclear weapons for ballistic missile delivery, to include delivery by ICBM-class missiles," a source told The Post, which cites a July 28 report by the Defense Intelligence Agency about North Korea’s capability of placing a nuclear warhead atop an intercontinental ballistic missile.
When was the most recent North Korean missile test?
On July 28. It was the country's 11th missile test so far this year.
What are U.S. defenses against a possible missile strike by North Korea?
The United States has a layered missile defense system designed to track and intercept a missile launch from North Korea. It includes missile interceptors aboard Navy ships in the Pacific and large ground-based interceptors located in Alaska and California. However, the viability of the large interceptors has been routinely questioned since they became operational nearly a decade ago because only half of the 18 interceptor tests have been successful.
In late May, the Missile Defense Agency successfully tested an interceptor that targeted an ICBM test missile fired from the Kwajalein Atoll in the South Pacific.
The Terminal High Altitude Area Defense (THAAD) system is a missile defense shield designed to intercept short- and medium-range missiles. In April, the United States deployed THAAD to South Korea for the first time, a long-planned move agreed to last summer after a series of North Korean missile tests. The United States has also placed the THAAD system in Guam, which could be a target of North Korea's long-range missiles.
What are the latest sanctions issued against North Korea?
The U.N. Security Council unanimously approved new sanctions on Aug. 5 to penalize the isolated regime for its escalating nuclear program and its recent ICMB launches.
The sanctions ban North Korean exports of coal, iron, lead and seafood products, estimated to be worth $1 billion a year.
North Korea slammed the penalties — which would slash a third of the country’s $3 billion in export revenue — as a “violent infringement of its sovereignty” and part of a “heinous U.S. plot to isolate and stifle” the country, according to a statement released through the state-run media outlet, Korean Central News Agency.
“It’s a wild idea to think the [Democratic People’s Republic of Korea] will be shaken and change its position due to this kind of new sanctions formulated by hostile forces,” Pyongyang said in a statement.
What are the options for dealing with North Korea?
In April, Secretary of State Rex Tillerson said that “all options are on the table” but warned that “if they elevate the threat of their weapons program to a level that we believe requires action, that option is on the table.”
Economic sanctions were widely considered to be the first realistic option. Now that further sanctions have been issued, the next possible steps are still being determined.