Russian President Vladimir Putin has reportedly signed into law a treaty on the country's strategic partnership with North Korea, which includes a mutual defense provision.

According to Russia's state-run TASS news agency, Putin signed the comprehensive strategic partnership treaty on Saturday.

Earlier, Russia's upper and lower houses both ratified the treaty unanimously.

The accord, signed by Putin and North Korean leader Kim Jong-un in June after their summit in Pyongyang, includes a mutual defense clause under which the two countries will provide military support to each other if either one comes under attack.

If North Korea also follows the procedures of ratification and signature and exchanges a letter of ratification with Russia, the treaty will take effect indefinitely.

North Korea has yet to make a public announcement that it has ratified or signed the treaty.