Thousands of Indians from the country's northeast fled southern cities on Thursday after rumours they would be attacked by Muslims in reprisal for recent ethnic violence, officials said.
Railway officials said they had put on extra trains from Bangalore to the northeastern state of Assam to accommodate a spike in demand after 6,000 tickets were sold since Wednesday evening.
People arriving in Assam's main city of Guwahati also told local television they had taken last-minute decisions to flee Hyderabad and the southern state of Kerala.
"We are investigating the source of these rumours and who is behind them," Bangalore deputy commissioner of police Vincent S. D'Souza told AFP.
"Mischief-mongers and vested interests are misusing social media, mobile and the Internet to spread these rumours and create panic in the people of the northeastern region," he added.
Three weeks of clashes in Assam between members of the local Bodo tribal community and Muslims have claimed 80 lives and displaced more than 400,000 people.
In New Delhi, Prime Minister Manmohan Singh appealed for calm.
"We have to maintain peace at any cost," the prime minister said and added that Indians must discount rumours.
"We must work together to ensure that all people from other states do not feel threatened by rumour mongering and SMS (text messages)," Singh told reporters, adding that he was in touch with chief ministers of the affected states.
Earlier Thursday violence flared again, with security forces called out in the Nalbari and Kamrup districts after mobs torched a bus, a car and a wooden road bridge.
In a separate incident 11 people were injured when acid was thrown at a group in the western Assam town of Gossaigaon in the troubled Kokrajhar district.
Police in the south said there were rumours that northeastern people, who look more East Asian or Tibetan than most Indians, would be attacked after the end of the Muslim holy month of Ramadan, around August 20.
There have been reports of isolated assaults in the southern cities of Pune and Mysore targeting people of northeastern appearance, while a rally by Muslims in Mumbai on Saturday protesting against the Assam unrest turned violent.
Two people were killed during the demonstration which came amid warnings from the police about anger in the Muslim community over the breakdown of law and order in parts of Assam.
On Wednesday night, thousands crammed into the main station in Bangalore, an IT hub that is a popular place to study for northeastern students, with many buying tickets to Assam or destinations in nearby West Bengal, officials said.
Police estimate that there are 240,000 people from the seven north-eastern states in Bangalore, which has population of nine million.
The chief ministers of Assam and Karnataka, the state that is home to Bangalore, also appealed for calm and said there was no reason for the exodus, as police took to Twitter and the local airwaves to knock down the rumours.
"Our police will offer full protection to you all. There is no reason to worry. Believe in our government and not in rumours," Karnataka chief minister Jagadish Shettar told about 200 northeastern students.
The unrest between Muslims and Bodos in Assam, which has repeatedly flared up in previous decades, is blamed by the Bodos and some politicians on an influx of illegal immigrants from nearby Bangladesh.
Muslims there claim they have been targeted by well-armed Bodo militias, which had previously been fighting their own separatist war.
Some 5,300 homes have been torched in the riots.
Anirban Das, a software engineer from Assam, told AFP that he had decided to flee Bangalore after hearing rumours about the danger.
"We heard we could be attacked and so boarded a train and reached Guwahati," he said.
The chief minister of Assam, Tarun Gogoi, urged students to stay where they were and not return home.