London (CNN) -- Police investigating the hit-and-run incident which killed three men protecting shops from potential looters in Birmingham, central England, arrested three males on Thursday.
The arrests come amid rising tensions and calls by community leaders and lawmakers urging locals not to retaliate against the deaths.
West Midlands police said two males aged 16 and 17 and a 26-year-old man were arrested on suspicion of murder. A 32-year-old man arrested on Wednesday has been released on bail.
The three victims -- Haroon Jahan, 21, and brothers Shazad Ali, 30, and Abdul Musavir, 31 -- were returning to a gas station they had been guarding in the early hours of Wednesday when the incident occurred, witnesses said.
Race-related violence had been a genuine concern, said Shabana Mahmood, the member of parliament for Birmingham.
The Winson Green area of Birmingham, where the hit-and-run took place, is an ethnically diverse area with a large Afro-Caribbean and Asian community.
The three men killed were of Asian origin and witnesses have described the men driving the car as Afro-Caribbean, Mahmood said.
"Obviously the early hours of Wednesday was a real danger point and we got through it. There were a lot of angry young Asian men who had gathered but seemed in the end to make the decision themselves that they were going to head the word of Tariq Jahan," said Mahmood.
Jahan, father of victim Haroon, had appealed for calm in the immediate aftermath of the deaths.
"Blacks, Asians, whites - we all live in the same community. Why do we have to kill each other? I lost my son. Step forward if you want to lose your sons. Otherwise, calm down and go home, please" he said.
Andrew Watson, Bishop of Aston in the Diocese of Birmingham, also expressed fears of race-related tensions.
"There were voices calling for retaliation, but these were increasingly drowned out by other voices (both old and younger) urging restraint."
Mahmood added: "People are still shocked and devastated but we've had two nights of calm and I'm hopeful there won't be any trouble."
Farooq Murad, Secretary General, Muslim Council of Britain, said: "I have just returned from the city (Birmingham) and have seen moving displays of solidarity between Muslims, Sikhs, Christians and Hindus.
"He (Tariq Jahan) did not ask for retribution. He did not engage in recriminations. He has not put his lot into the endless and polarised discussions currently taking place, passing judgment on why these riots took place and who, or what, is responsible. "
Police said a protest march in memory of the three dead men is expected to take place on Sunday.