Warsaw, July 10 (IANS): US President Barack Obama pledged the US long-term commitment to ensuring Europe's security and defending allies, while participating in his last NATO Summit before stepping down next January.

During his solo press conference after the closing of Warsaw NATO Summit on Saturday, Obama said the Alliance was strengthening its deterrence and defense capabilities and it was sending a clear signal: it is going to protect any of its members, Xinhua news agency reported.

"What will never change, is the unwavering commitment of the United States to the security and defense of Europe," Obama said.

He reminded that the Alliance had agreed on reinforcement of its collective defense and on deploying forces in Poland and Baltic states.

Obama also referred to the situation in Ukraine, saying that "Our 28 nations are united in our view that there can be no business as usual with Russia until it fully implements its Minsk obligations", and reminding that NATO confirmed its support for Ukraine.

On Britain's referendum to leave the EU, he expressed hopes that Britain's exit from the block could be as sensible as possible, causing possibly least damage to economy.

As a friend, ally and trading partner of Britain, Obama wished to see an orderly negotiating process and as close a relationship as possible in future.