Muslims in the South West are calling for calm following the bomb explosions on 7 July in London.
Sayed Wahid: Atmosphere has changed in the city
Police said the number of racist attacks was up since the attack on the capital which left more than 50 dead.
In one incident a 20-year-old Muslim youth received serious head injuries after he was attacked by a group of white youths in Central Park, Plymouth.
Some senior figures in the Islamic community are warning Muslims to keep a low profile while tensions are so high.
Eleven cases of suspected racist attacks have been reported to Devon and Cornwall's Police Diversity Unit since 15 July.
The type of person who is being attacked has also raised concerns in the unit.
The Jaipur restaurant's doorman has been abused
PC Simon Hardwick said: "All the victims are of Asian or Muslim description which is unusual. That raises concerns about a backlash."
The young Muslim attacked in Central Park had his head stamped on by a group of thugs who attacked him near basketball courts.
He is too scared to be identified, but he said he now planned to leave and he would not go out alone anymore.
Police have been holding meetings with leaders of minority groups who are being encouraged to report incidents.
Sayed Wahid, who owns the Jaipur Palace restaurant in Bretonside, Plymouth, said the atmosphere had changed dramatically since the bombing.
He said: "We have a person stand outside our restaurant with traditional Indian costume and he had never been abused before.
"They stopped the car and said 'Paki go home' and other abuse. It is since the bombing in London."
Mr Wahid, former chairman of the Islamic Centre and instrumental in creating the city's new Mosque in North Road East, said: "I think people should calm down. What happened in London we utterly condemn. This is nothing to do with Islam."
One of his daughters said since the bombings there had been an undercurrent of fear and suspicion in Plymouth where there are thought to be about 450 Muslims, including university students.
Wasia Wahid said: "It's not pleasant at all, especially because I was born in Plymouth and have grown up in Plymouth. My childhood, everything was here.
"But since this has all happened, it doesn't make you feel comfortable. It makes you feel like you're a stranger in your own home town. It makes you feel a little bit isolated."
Her undergraduate sister Shahnaz, who wears a Muslim headscarf, has suffered verbal abuse.
She said: "One young chap who was walking by he actually said, 'Are you sure you don't have a bomb on you? No?'. I was actually really stunned."