WASHINGTON - Treasury Secretary Janet Yellen will boycott several meetings of the powerful Group of 20 nations this week to protest Russia’s invasion of Ukraine, with a conference in Washington emerging as a key test for world leaders who have condemned the war.

Yellen will attend the opening session of the G-20 finance ministers’ meeting Wednesday to show support for Ukraine’s finance minister, who has flown in from Kyiv for the conference, according to a Treasury Department official who spoke on the condition of anonymity to share details of internal planning. But Yellen will skip other sessions over Russia’s presence, the official said. Russian Finance Minister Anton Siluanov is expected to attend the conference virtually. Siluanov was hit with U.S. sanctions earlier this year.

This week’s meetings - the first gathering of the G-20 since the war began - are emerging as a gauge of how the world’s leading international bodies will respond to Russian aggression. Many of the countries in the G-20 have condemned Russia, but some of its most influential members, such as China and India, have not. And many of the world’s wealthiest nations, including much of Europe, remain heavily dependent on Russian oil and natural gas even after the invasion, highlighting how deeply entangled Russia’s economy is with the rest of the world despite the severe sanctions the United States and its allies have imposed over the war.

At the meetings she is attending, Yellen will condemn Russia’s invasion and press to shut Russia out of global financial institutions, the Treasury Department official said. No countries from the Group of Seven industrialized nations are participating in a full boycott of the meetings, according to one person familiar with Yellen’s agenda who spoke on the condition of anonymity to share planning details.

“While Secretary Yellen and our partners will continue to work in solidarity to advance the important business of the G-20, she will also voice our strong condemnation of Putin’s brutality and make it clear that the benefits and privileges of the leading economic institutions of the world . . . are reserved for countries that demonstrate respect for the core principles that underpin peace and security across the world,” the Treasury Department official said.

Some critics suggested that Yellen should remain in the room to confront Russia directly over its actions, arguing that the meetings represent a rare opportunity for U.S. officials to challenge the Kremlin’s war effort. Yellen may skip G-20 sessions about sustainable finance that her Russian counterpart Siluanov is also expected to attend, for instance.

“I think it’s a mistake - getting into any forum where the U.S. can articulate our position is better than ceding territory or ceding the battlefield to Russia,” said Ariel Cohen, a senior fellow at the Atlantic Council’s Eurasia Center. “I understand a lot of the delegations are not professional communicators, but they can be trained. . . . They can make Russia’s presence there undesirable.”

The quandary over participation in the G-20 reflects a broader, growing problem for U.S. policymakers hoping to influence a world with increasingly powerful economic competitors. The smaller G-7 group, mostly close U.S. allies, has been more unified in condemning Russia. But as countries such as China and India have grown in economic might, Western leaders have increasingly been forced to collaborate with them to sway the global economic system. That has raised the relevance of the larger G-20, though that body remains harder for the United States to influence.

“The question of boycotting the G-20 - while a defensible and understandable action at this time - does raise the longer-term issue of how to manage a global economy with powerful and diverse actors,” said Mark Sobel, who spent four decades working on international economic issues at the Treasury Department and is now a senior adviser to the Center for Strategic and International Studies, a think tank. “To really steer the global economy, you need a bigger group than the G-7.”

President Biden has previously called for Russia to be expelled from the G-20 over the invasion of Ukraine. The G-20 is composed of 20 of the world’s largest economies. The group has no current process for kicking out its members, according to Sobel, but it could be possible to suspend Russia if a consensus emerges to do so.

Yellen will also meet this week with Ukrainian Prime Minister Denys Shmyhal and with international economic officials including the finance ministers of Saudi Arabia and Italy, the governor of the Bank of England, and the European commissioner of the economy.