Changes to the charter of one of China's top universities — dropping the phrase "freedom of thought" and adding a pledge to follow the Communist Party's leadership — have sparked heated debate and a rare act of student defiance.

The changes to the charter of Fudan University in Shanghai, which is considered one of China's more liberal institutions, came to light Tuesday when the education ministry said it had approved alterations for three universities.

Within hours, the Fudan amendments were trending on the Weibo social media platform, with one hashtag viewed more than a million times.