A Malaysian Catholic newspaper and church groups cried foul on Friday over a government move to forbid non-Muslims from using the word Allah.
The row could further strain race and religious relations in the country, where many non-Muslims believe their rights are being trampled by the Muslim majority.
The dispute came out in the open after Malaysia's internal security ministry ruled recently the term Allah -- long used by Christians in Malaysia to refer to God -- could no longer be used by non-Muslims.
"Malaysia is probably the only nation where the term Allah by Christians to refer to God is prohibited," parliamentary opposition leader Lim Kit Siang said in a statement, adding that the term was never banned even in the Middle East.
"The term Allah was used to refer to God by Arabic-speaking Christians before Arabic-speaking Muslims existed," he said.
-Malaysia faces Christian outcry over word "Allah"