Ukrainian officials claim that a "full-scale" invasion of their country has taken place. U.S. officials claims that more than 1,000 troops have crossed the Ukrainian border and are fighting alongside pro-Russian rebels. Russian President, Vladimir Putin, denies such reports. NATO claims satellite images prove Russia has indeed invaded Ukraine.

NATO has warned the international community that over 20,000 Russian troops have been placed upon the Ukrainian-Russian border for months. The escalating crisis forced the U.N. Security Council to meet on the matter.

Obama has promised to escalate economic sanctions upon Russia in response to the reported invasion.

Read more about the invasion here.