Yesterday (March 8, 2016) Iran tested ballistic missiles by launching them from silos across the country as a part of a military exercise. This act goes directly against the pressure that the United States and the international community has put on Iran the last few months. If you remember, the U.S. imposed sanctions targeting Iran's missile program and yesterday's tests suggest Iran pushing back and pretty much blatantly saying that they don't have to follow the rules.
Moreover, the United Nations claim that Iran's actions violate Security Resolution 1929, which prevents Iran "from undertaking any work on ballistic missiles capable of carrying nuclear warheads." This resolution was just removed two months ago when the Iran Nuclear Deal went through. However, a new resolution was implemented that pretty much tells Iran not to not test ballistic missiles and other technology with nuclear capabilities-so technically Iran didn't violate this new resolution.
Like a typical bad boy, Iran says they just want to show their power, which is why they say they do not have any nuclear weapons therefore they will continue missile development. Any missile test by Iran is a potential threat to U.S. allies in the Middle East as well as to U.S. military bases stationed in those countries. Instead of taking an aggressive approach U.S. officials have alluded to a diplomatic response and say that this issue will be pressed at the next U.N. Security Council meeting. Degrading Iran's nuclear and missile programs has been a priority for the U.S. and this seemingly defiant move by the country is alarming.
All in all, Iran is arguing that they are simply showing deterrence, but everyone else isn't buying this 'tough guy' act. The coming days will show whether or not the country is willing to talk it out and play nice but past actions suggest that bad boys never turn down the chance to fight.