Moscow: Russian President Vladimir Putin has signed a defense agreement between his country and North Korea that allows for "immediate military assistance" to each other in the event of an attack on either nation, TASS reports.According to Burkina Information Agency, the mutual defense agreement was reached during Vladimir Putin's visit to Pyongyang in June. The Upper House of the Russian parliament ratified the text on November 8, which still required President Putin's signature to come into force, a step that has now been completed.The agreement further commits the two states to cooperate internationally to oppose Western sanctions, coordinate their positions at the United Nations, and deepen their military cooperation.