Russia has revoked its right to launch military action in Ukraine.
The move, taken at the behest of President Vladimir Putin, was overwhelmingly approved; just three months after the Duma backed his request to consider such a motion.
Senior lawmakers said the move should be seen as an act of goodwill to facilitate peace efforts.
Russia’s actions to defend what it calls the rights of Ukraine’s Russian speakers have significantly boosted Putin’s wider popularity at home.
Ukraine has also welcomed Russia’s reversal as a positive step towards eventually ending the crisis.
“Now we have a positive step, but we need other positive steps also, like support of the comprehensive peaceful plan by the president, by Russia, and we need of course effective control at the border,” said Ukraine’s Foreign Minister Pavlo Klimkin during a visit to Brussels.
The crisis has also been the topic of a four-way phone call between the leaders of Germany, France, Russia and Ukraine, with Putin calling for the truce to be extended.
Ukraine’s President Poroshenko said a ceasefire will be maintained despite a deadly rebel attack on an army helicopter.