Kateryna Choursina, Volodymyr Verbyany and Bryan Bradley of Bloomberg are reporting that:
Ukrainian President Petro Poroshenko called an emergency security meeting to defend against what he called a Russian “invasion” after separatists gained ground in intensified fighting in eastern regions.
The AP adds that Poroshenko is staying in the country:
Poroshenko canceled a visit to Turkey for the inauguration of newly elected president Recep Tayyip Erdogan and called a snap session of Ukraine's security council.
"I have decided to cancel my visit to Turkey because of the sharp escalation of the situation in the Donetsk region… as Russian forces have entered Ukraine," he said.
And CNN says a U.S. official claims 1,000 Russian troops have entered Ukraine:
More from CNN:
Pro-Moscow rebel forces in eastern Ukraine, backed by Russian tanks and armored personnel carriers, battled government forces on two fronts Thursday, a Ukrainian military official said.
The fighting was taking place southeast of Donetsk, and along the nation's southern coast in the town of Novoazovsk, about 12 miles (20 km) from the Russian border, according to Mykhailo Lysenko, the deputy commander of the Ukrainian Donbas battalion.
"This is a full-scale invasion," Lysenko said, referring to the fighting in the south.
U.S. officials also said Russian troops were directly involved in the latest fighting, despite Moscow's denials.
Intelligence now indicates that up to 1,000 Russian troops have moved into southern Ukraine with heavy weapons and are fighting there, a U.S. official told CNN on Thursday.