A look at North Korea's past bluster and actual attacks

North Korea has a long track record of issuing threats and ultimatums that don't necessary lead to action. Then again, when it does act — often without warning — it can be fatal.

Here's a look at North Korean bluster, and cases where it's believed to have made good on threats, though in most of those cases it has denied carrying out attacks.

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2015: LANDMINES AND LOUDSPEAKERS

Kim Jong Un issued an ultimatum that seemed to bring the Koreas very close to a war footing in August 2015. Tensions had escalated rapidly after land mines maimed two South Korean soldiers along the Demilitarized Zone. The confrontation deepened as the South demanded an apology and re-started propaganda broadcasts over loudspeakers near the DMZ. It was defused at the last minute by marathon talks.

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2014: THE SONY HACK

Washington claims North Korea carried out this massive hack in 2014 to get revenge against Sony Entertainment for distributing "The Interview," a black comedy that ended with graphic images of Kim Jong Un being enveloped in a fiery explosion. Pyongyang had warned it would retaliate before the movie's release, threatening attacks on the White House and other targets in the United States. It has denied responsibility for the hack, but praised the hackers.

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2013: A THREAT ON GUAM OVER B-52 BOMBERS

In an escalation of threats in March 2013 similar to what is going on now, North Korea warned that Guam was within striking range of its missiles. The threat came as the United States announced a plan to send B-52 bombers over South Korea for military exercises with Seoul. It was considered serious enough to warrant the deployment of missile interceptors, but in the end dissipated without incident.

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2010: ISLAND SHELLING

On Nov. 23, 2010, the North hammered the South Korean island of Yeonpyeong, firing off 170 shells and rockets that hit military and civilian targets and killed four South Koreans. The North claimed the incident was triggered by South Korean artillery drills and the South's firing of rounds into the North's territorial waters. It occurred as tensions were unusually high — that same day, the U.S. and South Korea began annual, large-scale military exercises.

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2010: SINKING OF THE CHEONAN

On March 26, 2010, the South Korean corvette Cheonan sank in the Yellow Sea after being hit by what is believed to have been a torpedo. Forty-six South Korean sailors died. North Korea denied it attacked the ship and refutes the findings of a subsequent international panel. But many saw it as possible retaliation for a clash with the South several months earlier off the west coast of the Korean Peninsula that left two North Koreans dead.

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2002: THE AXIS OF EVIL

North Korea reacted to President George W. Bush's claim that it was part of an "Axis of Evil" by issuing a warning through its Foreign Ministry that the U.S. isn't the only country that can attack its adversaries and said it would "mercilessly wipe out the aggressors." So far, it hasn't.