Trump tweeted on Sunday (24 September).
According to Dana White, a Pentagon spokeswoman, the flights were "the closest that any USA plane has flown to the demilitarized zone in the 21 century and underscores the seriousness with which we take the reckless behavior of North Korea".
The foreign minister said that Trump, as America's current leader, had issued a "clear declaration of war".
The war of words between Trump and Kim Jong-un has been escalating for some time, and the North Korean leader has threatened to shoot down United States aircraft even if they are not in North Korean airspace.
However, the U.S. and North Korea are still technically at war, as the 1953 conflict ended in a ceasefire. Users are not allowed to "incite or engage in the harassment of others" or "promote violence against or directly attack or threaten other people on the basis of race, ethnicity, national origin, sexual orientation, gender, gender identity, religious affiliation, age, disability, or disease". Any accounts that engage in such behaviour may be removed or subject to temporary suspension, it says.
Twitter insists that it holds all users accountable to the same rules, but points out that the "newsworthiness" of a tweet is also taken into consideration. The company pledged to update its public politics on the factors that may lead to a tweet being taken down from the site. "Donald Trump's tweet about North Korea may have riled that nation's representatives, but according to a thread from its global public policy team, "newsworthiness" and whether a Tweet is of public interest" comes into play. "This has always been an internal policy and we'll soon update our public-facing rules to reflect it. We need to do better on this, and will", the tweets continued. "We're putting significant effort into increasing our transparency as a company, and commit to meaningful and fast progress". The suggestion is that if other Twitter users were to say similar things, it would be perceived as a threat of violence and Twitter would step in and either delete the tweets or ban the user. If he decides to declare war on Twitter, it will be newsworthy.
Trump also specifically threatened Ri on Twitter, suggesting he "won't be around much longer" if he continues on a path of escalation with the US. Sometimes he tweets about Hurricane Maria, but not almost as often as people expect the president to tweet about a devastating natural disaster.