(Reuters) - Hundreds of thousands of people protested in Russia's Chechnya region on Monday against what its Kremlin-backed leader called the "vulgar and immoral" cartoons of the Prophet Muhammad published by French newspaper Charlie Hebdo.

Mixing pro-Islamic chants and anti-Western rhetoric, Chechen leader Ramzan Kadyrov criticized Europe to chants of "Allahu Akbar" (God is greatest) as the protesters stood along the main thoroughfare of Chechnya's capital, Grozny.

Some carried signs declaring "I love my Prophet Muhammad" in English and others waved flags, as security service helicopters flew overhead and police stood by.

In a sign that it had President Vladimir Putin's backing, the rally was shown live on state television. The Kremlin may see the protest as a way to vent pressure from Russia's Muslims after a similar rally was banned in Moscow.

"If needed, we are ready to die to stop anyone who thinks that you can irresponsibly defile the name of the prophet," Kadyrov said, wiping away tears on stage.

"You and I see how European journalists and politicians under false slogans about free speech and democracy proclaim the freedom to be vulgar, rude and insult the religious feelings of hundreds of millions of believers," he said.

The rally ended when a call to prayer was blasted over loudspeakers.

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.

Demonstrations have taken place in several Muslim countries since then, some turning violent. French President Fran├žois Hollande said anti-Charlie Hebdo protesters do not understand France's attachment to freedom of speech.

Russia's Interior Ministry said 800,000 people had attended the rally -- about 60 percent of Chechnya's population. Reuters witnesses put the number at several hundred thousand.

Kadyrov is barred from entering the United States, for alleged human rights abuses, and the European Union, under sanctions related to Russia's actions in Ukraine. He has used rallies before to demonstrate loyalty to Putin, though some say they are forced to attend.

Kadyrov is fighting against an insurgency aimed at creating an Islamist state in the North Caucasus and depends on Russian money and security forces to maintain an uneasy peace.

Some state-controlled and Kremlin-friendly media in Russia, where laws forbid offending religious sentiments, have questioned the value of free speech since the Paris killings.