(CNN) -- Attackers firebombed three churches in the southeast Asian nation of Malaysia overnight, assaults that come amid widespread Muslim ire over a court ruling that allowed Christians to use the word Allah as a term for God.
Malaysian news reports said no casualties have been reported, and police have promised to step up security for churches and other places of worship.
But the acts stirred unease in the diverse society -- where 60 percent of the people are Muslim, 19 percent are Buddhist, 9 percent are Christian and 6 percent are Hindu.
"We regret the irresponsible actions of certain extremist elements for the recent spate of firebombs thrown into church premises. These actions display their immaturity and intolerance toward others within a multi-racial society," the National Evangelical Christian Fellowship of Malaysia said in a statement.
The violence comes as Muslims protest a recent court ruling that allowed a Catholic newspaper to use the word "Allah" for God. Muslims believe Allah, an Arabic word, should only be used by Muslims. A stay has been placed on the order on the grounds of national interest.
Muslims took to the streets Friday to protest the use of the word by non-Muslims, and authorities such as Malaysian Prime Minister Najib Razak called for the matter to be resolved in court amicably and expressed hope the protests don't deteriorate.
"We should not raise the tension level in this country," he said Thursday, as quoted by Bernama, the Malaysian National News Agency.
Yang di-Pertuan Agong Tuanku Mizan Zainal Abidin, Malaysia's head of state, on Friday called for calm and the spirit of unity, according to a Bernama report.
The three churches attacked were in the Kuala Lumpur region. They are the Metro Tabernacle Church, the Assumption Church and the Life Chapel. The attacks occurred late Thursday night and early Friday.
"It's incumbent upon the Malaysian government to investigate the church bombings and to prosecute the perpetrators of this religiously motivated violence," said Leonard Leo, chairman of the U.S. Commission on International Religious Freedom, an independent federal agency that makes recommendations to Congress and the president regarding how to handle violations of religious freedom around the world.
"There are many parts of the world where Christians do use the world 'Allah' in their translations of the Bible," he told CNN in a telephone interview. "So the Malaysian Supreme Court ruling that overturns the government's ban on the use of the word is not inconsistent with what the practice would be elsewhere around the world. The Malaysian ban is what's unusual, not the court's ruling."