Four Malaysian churches were attacked with firebombs, causing extensive damage to one, as Muslims pledged Friday to prevent Christians from using the word “Allah,” escalating religious tensions in the multiracial country. Many Malay Muslims, who make up 60 percent of the population, are incensed by a recent High Court decision to overturn a ban on Roman Catholics using “Allah” as a translation for God in the Malay-language edition of their main newspaper, the Herald. The government says Allah, an Arabic word that predates Islam, is exclusive to the faith and by extension to Malays. It refuses to make an exception, even though the Herald's Malay edition is read only by Christian indigenous tribes in the remote states of Sabah and Sarawak. At Friday prayers at two main mosques in downtown Kuala Lumpur, young worshippers carried banners and gave fiery speeches, vowing to defend Islam. “We will not allow the word Allah to be inscribed in your churches,” one speaker shouted into a loudspeaker at the Kampung Bahru mosque. About 50 other people carried posters reading “Heresy arises from words wrongly used” and “Allah is only for us.” “Islam is above all. Every citizen must respect that,” said Ahmad Johari, who attended prayers at the National Mosque. “I hope the court will understand the feeling of the majority Muslims of Malaysia. We can fight to the death over this issue.” The demonstrations were held inside the mosque compounds to follow a police order against protests on the streets. Participants dispersed peacefully afterward. Malaysia is often held up as a model for other Muslim countries because of its economic development, progressive society and generally peaceful coexistence between the Malay majority and the ethnic Chinese and Indian minorities who are mostly Christians, Buddhists and Hindus. The Allah controversy, however, has the potential to shatter that carefully nurtured harmony, drive a deep racial wedge and scare away sorely needed foreign investment as the country struggles to emerge from the global financial crisis.