Russia pressed Ukraine to call a ceasefire in its battle to wrest control of eastern Ukraine from rebels, but Ukraine's leaders responded today with defiance.
“A great war has come, the likes of which Europe has not seen since the Second World War,” Ukrainian Defense Minister Valeriy Heletey said on his Facebook page today.
Heletey's comments implied that Ukraine was entering combat with Russia. Ukraine and NATO allege that Russia has sent troops and armor across the border when it appeared that pro-Russian rebels were losing to Urkaine's military forces.
On another front, Russia's actions have prompted NATO to form a 4,000 troop "spearhead" force to counter any Russian aggression.
Here's what we know so far:
What is going on in Ukraine?
Ukraine's momentum was abruptly reversed last week as the Ukraie military was closing in on the rebels strongholds Donetsk and Luhansk. Since then, the rebels opened up a new front further south seizing the city of Novoazovsk, and menacing the port city of Mariupol.
Officials in Kiev and Western countries allege Russia has sent in troops and equipment to bolster the pro-Russia rebels, but Moscow denies it and rejects suggestions that it can wield influence over the rebels.
How many Russian troops are currently in Ukraine?
Despite the Russian denials, Ukrainian National Security Council spokesman Col. Andriy Lysenko said Monday that "not less than four battalions and tactical groups of the Russian armed forces are active in Ukraine." A battalion consists of about 400 soldiers.
Last week, a rebel commander said there were 4,000 Russian soldier fighting with the rebels. Those soldiers were on vacation, the commander said.
Where have there been clashes?
Clashes between Russian separatists and Ukrainian forces have been reported in Donetsk and Luhansk regions. Luhansk Airport, located in the eastern most corner of the country, has been taken over by separatist forces of the self-proclaimed Luhansk People’s Republic.
Tanks and soldiers from the Russia-backed insurgents have not yet made it to the coastal town of Mariupol, but residents fear that they are next since their port city is along the Azov Coast. The tourist destination of Novoazovsk, also along the coast but closer towards the Russian border, was reportedly seized by the rebel forces late last week.