Police in Bombay, India, opened fire Friday on Moslem mobs protesting "The Satanic Verses," killing up to 12 people, and an Iranian leader said the novel might cause a "vast battle" between Iran and the West.

Officials in London said Britain asked Soviet Foreign Minister Eduard A. Shevardnadze to press the Iranian patriarch, Ayatollah Ruhollah Khomeini, to lift his command that followers kill Salman Rushdie, author of the novel Moslems call blasphemous.News reports said police gunfire wounded 40 people during the Bombay protest by about 5,000 people after midday Moslem prayers and that 11 police officers were injured. Police said they arrested 300 demonstrators.

The protesters ignored a ban on assembly of more than five people in public places Friday, the Moslem sabbath. A police spokesman said they set fire to several buses and other vehicles and attacked police.

Police imposed the ban after some Moslems announced plans to demonstrate against the book. Reports of the death toll conflicted. Press Trust said 12 people were killed, United News of India put it at 10, and Police Commissioner S.M. Shangari said eight had died. Two deaths initially attributed to the violence were caused by unrelated road accidents, he said.

Demonstrations also were reported in the Indian cities of New Delhi, Calcutta, Darjeeling, Varanasi, Patna and Siliguri. No violence was reported.

In New Delhi, about 400 Moslems marched to the British Embassy, and the city's 32-officer police force was put on alert.

India banned Rushdie's book in November, fearing it could spark sectarian unrest. More than 90 million Moslems live in India and make up about 11 percent of the nation's population of 880 million. The novel also is banned in Pakistan, South Africa, Bangladesh, Iran and Egypt.

Rushdie was born into a Moslem family in Bombay in 1947. Now a British citizen, he has been under police guard in England since Feb. 14 when Khomeini first ordered Moslems to kill him. Iranian clerics have put a $5.2 million bounty on Rushdie's head.

In demonstrations Feb. 12-13, one person was killed in India and six died in Pakistan, where police opened fire on a crowd that attacked a U.S. diplomatic office.

Iran's Parliament speaker, Hashemi Rafsanjani, urged Western countries to state clearly if they agree with the contents of Rushdie's novel.