Grozny - Tens of thousands of people staged a rally on Monday in Russia's Chechnya region against French magazine Charlie Hebdo's cartoons of the Prophet Muhammad, which the predominantly Muslim region's leader denounced as "vulgar and immoral".Carrying signs declaring "Hands off the Prophet Muhammad", men in traditional Chechen dress and women and children shouted "Allahu Akbar" (God is greatest) as they streamed down the main thoroughfare of Chechnya's capital, Grozny, rebuilt after two separatist wars in the North Caucasus region.French satirical magazine Charlie Hebdo published a picture of Muhammad weeping on its cover last week after gunmen stormed its offices, killing 12 people. The gunmen said the attack was revenge for cartoons the magazine had published mocking Islam."We will launch a decisive protest against the vulgarity, immorality, lack of culture and shamelessness of those who drew the caricatures of the Prophet Muhammad [peace be upon him]," Chechen leader Ramzan Kadyrov wrote online before the rally."We publicly warn that we will not tolerate similar actions," he said. Kadyrov said he expected up to 1 million people to attend the rally.Kremlin-backed Kadyrov, who opposes an insurgency that aims to carve out an Islamist state in the mostly Muslim North Caucasus, has cultivated his own brand of Islam which critics say contradicts Russian law.Mass rallies organised in the region have been used to show Kadyrov's allegiance to Moscow. Around 100 000 were estimated to have marched in Grozny at a rally organised for the birthday of President Vladimir Putin last year.Some participants in other rallies have criticised Chechen authorities, saying they were forced to attend.Some state-controlled and Kremlin-friendly media in Russia, which has passed a law making it illegal to offend religious sentiment, have questioned the value of free speech since the Paris killings.