Four years after cartoons of the prophet Muhammad set off violent protests across the Muslim world, Islamic nations are mounting a campaign for an international treaty to protect religious symbols and beliefs from mockery.

It would essentially mean a ban on blasphemy that would put them on a collision course with free speech laws in the West, The Associated Press said Thursday in Geneva.

Algeria and Pakistan have taken the lead in lobbying to eventually bring the proposal to a vote in the UN General Assembly, according to documents obtained by The Associated Press.

If ratified in countries that enshrine freedom of expression as a fundamental right, such a treaty would require them to limit free speech if it risks seriously offending religious believers. The process, though, will take years and no showdown is imminent.

The proposal faces stiff resistance from Western countries, including the United States, which in the past has brushed aside other UN treaties, such as one on the protection of migrant workers.

Experts say the bid stands some chance of eventual success if Muslim countries persist. And whatever the outcome, the campaign risks reigniting tensions between Muslims and the West that President Barack Obama has pledged to heal, reviving fears of a "clash of civilizations."

In 2005, a Danish newspaper published cartoons lampooning the prophet Muhammad, prompting angry mobs to attack Western embassies in Muslim countries, including Lebanon, Iran and Indonesia. In a counter-movement, several European newspapers reprinted the images.

The countries that form the 56-member Organization of the Islamic Conference are now lobbying a little-known Geneva-based UN committee to agree that a treaty protecting religions is necessary.

The move would be a first step toward drafting an international protocol that would eventually be put before the General Assembly — a process that could take a decade or more.