Moscow, Jul 11 (IANS): The expansion of the North Atlantic Treaty Organisation (NATO) into Ukraine is an "unacceptable threat" to Russia's security, Kremlin Spokesman Dmitry Peskov said Thursday.

Peskov's remarks came following a joint declaration adopted Wednesday at the NATO summit in Washington, which stated that "Ukraine's future is in NATO."

Peskov said that the alliance is "de-facto fully involved in the Ukrainian conflict," adding that its military infrastructure is progressively moving towards Russia's borders, reported Xinhua news agency.

"From the very beginning, we said that NATO expansion into the territory of Ukraine is an unacceptable threat to us, our existence, our security," Peskov said.

He said the measures adopted at the summit compel Russia to take appropriate steps to contain the bloc since it may threaten the country's national security.

"This will require us to form thoughtful, coordinated and effective response measures to contain NATO," the spokesperson said.