DUBAI (REUTERS) - Iran's top leader Ayatollah Ali Khamenei tweeted a tribute to a prominent Shi'ite executed by Saudi Arabia on Saturday, adding his voice to a chorus of condemnation in Iran and beyond.

Saudi Arabia executed Nimr al-Nimr and three other Shi'ites alongside dozens of Al-Qaeda members of Saturday, signalling it would not tolerate attacks by either Sunni militants or members of the Shi'ite minority seeking equality.

"Awakening is not suppressible," read the tweet on Khamenei's English-language Twitter account, next to a photograph of Nimr.

Khamenei's website also carried an image comparing Saudi Arabia to extremist group Islamic State in Iraq and Syria, suggesting that they both execute their opponents.