Over 1,000 Russian troops were fighting aloside ngpro-Russian separatists in eastern Ukraine, said a Nato officer, as reported by WSJ.
Russian forces have seized the coastal town of Novoazovsk and several villages near the border with Russia, said Kiev. Followed by this, Ukraine's President Petro Poroshenko called for an emergency meeting of the United Nations Security Council and the European Council.
Ukraine's ambassador to the Organization for Security and Cooperation in Europe said there was a "direct invasion of the Russian military".
However, Russia has denied that any Russian troops were in Ukraine. But separatist rebels in Ukraine said Russian active duty military are fighting in Ukraine.