Updated

Worshippers found severed heads of pigs at two Malaysian mosques Wednesday following a spate of firebomb attacks on churches amid a dispute over the use of the word "Allah" by Christians, officials said.

The incident is the most serious to hit Islamic places of worship following vandalism and other assaults at 11 churches, a Sikh temple, a mosque and two Muslim prayer halls across this Muslim-majority country in the past three weeks.

The attacks followed outrage among Muslims over a Dec. 31 court verdict that allowed non-Muslims to use "Allah" as a translation for "God" in the Malay language. Many Malaysian Muslims believe the word should be exclusive to their religion, and that its use by others could confuse some Muslims and even lure them to convert.

Several men who went to a suburb mosque to perform morning prayers Wednesday were shocked to discover two bloodied pig heads wrapped in plastic bags in the mosque compound, said Zulkifli Mohamad, the top official at the Sri Sentosa Mosque on the outskirts of Kuala Lumpur, Malaysia's largest city.

Pigs are considered unclean by Muslims.

Two severed pig heads were also found at the Taman Dato Harun mosque in a nearby district, said the mosque's prayer leader, Hazelaihi Abdullah.

"We feel this is an evil attempt by some people to aggravate tensions," Zulkifli told The Associated Press.

Government authorities have denounced the attacks on places of worship as a threat to decades of amicable relations between ethnic Malay Muslims, who make up nearly two-thirds of Malaysia's 28 million people, and religious minorities, mainly ethnic Chinese and Indians who practice Buddhism, Christianity or Hinduism.