John Kerry is meeting with Russian Foreign Minister Sergei Lavrov tomorrow regarding the crisis in Crimea, and in advance of that meeting, Kerry offered a sternly-worded statement today, NBC News reports. If Crimea's planned referendum on whether to join Russia goes forward on Sunday and, based on Russia's response, there are no signs of "any capacity to be able to move forward and resolve this issue, there will be a very serious series of steps on Monday in Europe and here with respect to the options that are available to us," Kerry said, according to AFP. (More John Kerry stories.)