Hong Kong (CNN) -- In Asia, Indian Prime Minister Narendra Modi has called Vladimir Putin a "dear friend." Chinese leader Xi Jinping went a step further, calling the Russian president his "closest and best friend."

But Russia's war in Ukraine has cast doubt on Russia's previously warm relations with Asian powers such as China and India.

Both China and India have refused to condemn Russia's brutal invasion and both abstained from voting on United Nations Security Council and General Assembly resolutions demanding Moscow immediately stop its attack on Ukraine.

But with the United States making it clear that it views countries that do not condemn Putin's war as aligned with Russia, the world's two most populous nations face increased international pressure to speak out, or risk being seen as complicit.

That neither country has chosen to do so has exposed Russia's enormous influence in Asia, where arms sales and untethered trade have allowed Moscow to exploit regional fault lines and weaker ties with the West.

In the United States and Europe, leaders have framed their response to the invasion as part of a broader ideological battle to defend democratic freedoms and the rule of law. But for two of Asia's major powers, those lines are more blurred, with experts suggesting India and China are more motivated by self-interest.