New measures announced by the leaders during the May 19-21 meetings will target sanctions evasion involving third countries, and seek to undermine Russia's future energy production and curb trade that supports Russia's military, the people said.

Separately, U.S. officials also expect G7 members will agree to adjust their approach to sanctions so that, at least for certain categories of goods, all exports are automatically banned unless they are on a list of approved items.

The Biden administration has previously pushed G7 allies to reverse the group's sanctions approach, which today allows all goods to be sold to Russia unless they are explicitly blacklisted.

That change could make it harder for Moscow to find gaps in the sanctions regime.

While the allies have not agreed to apply the more-restrictive approach broadly, U.S. officials expect that in the most sensitive areas for Russia's military G7 members will adopt a presumption that exports are banned unless they are on a designated list.

The exact areas where these new rules would apply are still being discussed.

"You should expect to see, in a handful of spaces, particularly relating to Russia's defense industrial base, that change in presumption happen," said a U.S. official who declined to be named.

The precise language of the G7 leaders' joint declarations is still subject to negotiation and adjustment before it is released during the summit. The G7 comprises the United States, Japan, Canada, France, Germany, Italy and the United Kingdom.

The G7 leaders' action on Russia comes as Ukraine's Western allies hunt for new ways to tighten already restrictive sanctions on Russia, from export controls to visa restrictions and an oil price cap, which have put pressure on Russian President Vladimir Putin but not halted the full-scale invasion that started over a year ago.

Some U.S. allies have resisted the idea of banning trade broadly and then issuing category-by-category exemptions.

The European Union, for instance, has its own approach and is also currently negotiating its 11th package of sanctions since Russia invaded Ukraine, with the bulk focused on people and countries circumventing existing trade restrictions.

"The sometimes-discussed approach of 'we ban everything first and allow exceptions' will not work in our view," said one top German government official. "We want to be very, very precise and we want to avoid unintended side effects."

Meanwhile, any change in language, including language specifying that certain trade is banned unless specifically exempted, by the G7 leaders may not necessarily lead to more bans immediately or indeed any change in Russia's posture.

"At least on day one, that change in presumption doesn't change the substance of what's allowed, but it matters for the long-term trajectory of where we're going and the restrictiveness of the overall regime," the U.S. official said.

Ukraine, backed by Western arms and cash, is expected to launch major counter-offensive operations in the coming weeks to try to recapture tracts of its east and south from Russian forces.

Ukrainian President Volodymyr Zelenskiy has been in Europe this week for meetings with Pope Francis as well as with leaders from France, Italy and Germany. He is expected to address G7 leaders, either virtually or in-person, during their summit in Hiroshima, the officials said.

Former Russian President Dmitry Medvedev said last month a G7 move to ban exports to the country would cause Moscow to terminate a Black Sea grain deal that enables vital exports of grain from Ukraine. Food security in the aftermath of the war is also expected to be a major topic at the G7.