Russian propaganda is spreading in Spanish and Arabic and in places outside the West.

When Russia’s war in Ukraine began, Facebook, Twitter and other social media giants moved to block or limit the reach of the accounts of the Kremlin’s propaganda machine in the West. The effort, though, has been limited by geography and language, creating a patchwork of restrictions rather than a blanket ban.

In Spanish in Latin America or in Arabic across the Middle East, a steady stream of Russian propaganda and disinformation continues to try to justify President Vladimir V. Putin’s invasion, demonizing Ukraine and obfuscating responsibility for Russian atrocities that have killed thousands of civilians.

The result has been a geographical and cultural asymmetry in the information war over Ukraine that has helped undercut American- and European-led efforts to put broad international pressure on Mr. Putin to call off his war.

And the failure of Facebook, Twitter and TikTok, the Chinese-owned app, to impose stronger checks on Russian posts in non-English languages has begun to draw criticism as the war drags on.

“There is not an airtight, worldwide stifling of Russia’s notorious ability to fight not only on the battlefield, the real battlefield, but also to fight with information and distortions of information,” said Paul M. Barrett, deputy director of the Stern Center for Business and Human Rights at New York University, who recently wrote a study about the spread of harmful Russian propaganda on YouTube.