Russia-Ukraine updates: US to ban Russian carriers from its airspace

In a press briefing at NATO headquarters in Brussels, NATO Secretary-General Jens Stoltenberg urged Russia to "choose the path of diplomacy," as he said that Russia's aggressive behavior towards Ukraine marks "the most dangerous moment in European security in a generation."

Stoltenberg said that there is evidence that Russia has already entered Ukraine, going as far as saying that Russia has been in Donbas since 2014 in what he considers "covert" operations. He said Russia has now moved from "covert attempts to destabilize Ukraine to overt military action."

Russia has deployed over 150,000 troops, fighter jets and attack helicopters in Ukraine and Belarus and along the Russia-Ukraine border, with troops "in the field and ready to attack," according to Stoltenberg, while NATO allies have deployed more troops in Romania, Estonia, and Lithuania, and more than 120 ships and over 100 jets are on "high alert." The NATO response force is on "high readiness," but has not been deployed.

Stoltenberg said that it is "never too late not to attack," and that options for diplomacy are still available to Russia, even despite Putin's "threatening rhetoric" in his address to the public Monday. "We are ready to talk," said Stoltenberg, as NATO continues to look for a "political path forward."

-ABC News' Christine Theodorou

Russian President Vladimir Putin held a press conference on the situation around Ukraine following the Russian Parliament granting him permission to use military force outside of the country Tuesday.

Putin warned Russia was ready to provide "military assistance" to the two separatist self-proclaimed republics in eastern Ukraine and send troops there "in the case of necessity," claiming that a "conflict" was continuing on the ground, while Ukrainian officials have said Russia is the aggressor there. 

"As a conflict is happening there, in the case of necessity we are determined to carry out of our obligations we have taken on," Putin said. 

In a significant statement, Putin said that Russia recognizes the separatists' larger territorial claims, which would include the whole of Ukraine's Donbas region, not just the area they currently hold -- declaring the Minsk agreements to no longer exist.

He added that Western countries should now agree to the "demilitarization" of Ukraine and repeated it would be best if Ukraine publicly renounced its ambitions now to join NATO.

-ABC News' Patrick Reevell

Russia's upper house of parliament voted unanimously on Tuesday to grant Russian President Vladimir Putin permission to deploy military force outside of the country -- in a move that could signal military forces being deployed beyond the Russian-backed separatist regions.

The vote comes after Putin recognized the independence of two separatist regions in eastern Ukraine on Monday, escalating fears the Russian leader is paving the way for a larger invasion.

The Russian leader is currently speaking following the Federal Council granting him permission.

Western leaders have condemned Putin’s decision and warned of imposing more economic sanctions if Russia attacks Ukraine.

-ABC News' Christine Theodorou

The European Union has published the proposals of targeted measures that will be formally tabled Tuesday afternoon in response to Moscow’s recognition of the separatist regions in eastern Ukraine -- and adds that they have prepared and stand ready to adopt additional measures if needed.

In a statement from the presidents of the European Commission and the European Council on Russian aggression against Ukraine, the group labeled Russia’s actions as “illegal and unacceptable.”

"It violates international law, Ukraine's territorial integrity and sovereignty, Russia's own international commitments and it further escalates the crisis. Both Presidents welcome the steadfast unity of Member States and their determination to react with robustness and speed to the illegal actions of Russia in close coordination with international partners,” they said.

The package contains proposals to target individuals involved with the decision to recognize Russian-backed separatist regions, banks financing the move, Russian access to EU markets and trade from the two breakaway regions.

An informal meeting of EU Foreign Affairs Ministers chaired by the High Representative is scheduled for 4 p.m. where the first package of sanctions will be formally tabled later this afternoon. Appropriate bodies will then meet to finalize the package.

-ABC News' Christine Theodorou