NHK has obtained the Group of Seven draft statement on Ukraine, a final version of which will be released during the upcoming leaders' summit in Hiroshima.
It condemns Russia's invasion, and vows to make every effort to restore peace in the country.
Japan, the chair of the summit that opens on Friday, has been coordinating with its G7 peers to release a statement on Ukraine, separate from the leaders' declaration.
The draft calls Russia's aggression an unjustifiable and unprovoked war of invasion that disregards the Charter of the United Nations.
It also points out that the war is impacting countries with vulnerable food and energy security positions. It says the G7 denounces Russia in the strongest possible terms.
The document calls on Russia to pull all its troops out of Ukraine immediately and without conditions. It stresses that enduring peace cannot be achieved without Russia's withdrawal.
The draft warns that there will be serious consequences should Russia use nuclear, biological or chemical weapons.
It cites a declaration adopted at last year's G20 summit in Indonesia, which Russia took part in, that said, "The use or threat of use of nuclear weapons is inadmissible."
The document vows to ensure Ukraine will be provided the economic assistance it needs.
It also pledges to extend assistance for the countries and people adversely affected by the situation in Ukraine, with the emerging and developing nations collectively called "Global South" in mind.
In the conclusion, it says the G7 leaders vow from Hiroshima, a city symbolizing peace, to make every effort to bring enduring peace to Ukraine as soon as possible by mobilizing all policy measures.
The Japanese government plans to consider adding more specific descriptions regarding sanctions against Russia and some other issues. It also aims to incorporate the outcome of discussions by the G7 leaders at the summit.