Christians Tuesday demanded a probe into a mob attack on American missionaries accused of trying to convert Hindus, saying police inaction would trigger many such incidents in future.

The missionaries, who were attacked by the mob Saturday during a Bible reading session in the Malwani suburb, were deported Monday by the immigration department for indulging in preaching activities despite holding tourist visas.

"It (the attack) is a very unfortunate incident. We will take it up at the highest level to ensure that this kind of incident is not repeated again," said Dolphy D'Souza, president of the Bombay Catholics Sabha.

"It's not a normal law and order problem. The administration has to be more vigilant to prevent cases like this. It's not a banana republic where a group of people can bash up anyone by making false allegations," D'Souza told IANS.

"This attack needs to be probed and the guilty must be punished at the earliest. Otherwise it will sent a very wrong signal about the image of a progressive city like Mumbai to the outside world."

A group of local Christians are likely to meet Maharashtra Chief Minister Vilasrao Deshmukh and Home Minister R.R. Patil to lodge a protest.

A mob of nearly 30 men attacked three US-based missionaries, part of a group of eight who were visiting the city, Saturday night on grounds that the preachers were trying to convert local Hindus by offering money.

While four of the eight missionaries of the North Carolina-based Church of Christ were deported Monday for violations of the country's visa regulations, the others had left the city Sunday itself.

D'Souza, however, denied that the missionaries flouted visa conditions to enter the country for religious reasons.

"The Bible reading session organised by the priests was a private function. It was not one of those public religious discourses that are attended by hundreds of people. That's why they had applied for the tourist visa," he said.

"And even if they violated the visa guidelines, the law should have taken its own course. The discrepancy in the visa norm doesn't justify the mob attack on the missionaries," added D'Souza.

A local Christian priest, who didn't want to be named, charged the police with not taking action against the attackers and, instead, focussing on the deportation of missionaries.

"They picked up only two assailants while it was a group of 30 people. Moreover, those two were also released on bail on the same day. This will give leeway to others to behave like hooligans," he said.

Meanwhile, Mumbai Police said they were continuing with their investigation into the case and that all the guilty would be brought to book.                      

"While we are trying to find out who all were involved in the attack, we are also trying to establish whether conversion was really happening in that area. No one has, so far, lodged a complaint with us on conversion," said an official.