Indian authorities suspended two policemen and made four more arrests over a mob attack on a Tanzanian student in Bangalore, police said Friday, in a case that has caused widespread outrage.

A mob attacked the 21-year-old woman as she drove with friends in the southern city on Sunday night, beating her, ripping off her shirt and setting the car ablaze.

Nine people have now been arrested over the assault, which came in apparent revenge for a fatal road accident in which a Sudanese man had allegedly run over a woman less than an hour before.

READ: Indian mob strips, molests and beats Tanzanian student

"We have arrested four more persons on Thursday night in the assault case of Tanzanian woman, taking the total to nine, including five Thursday morning," N.S. Megharik, Bangalore police commissioner, told reporters.

Two police constables who were at the scene were suspended for failing to stop the mob from attacking the foreigners and for not registering a complaint, the commissioner said.

The incident sparked national outrage with foreign minister Sushma Swaraj branding it as "shameful", while the Tanzanian High Commission has lodged a strong protest, suggesting it may be racially motivated.

Tanzanian High Commissioner John W. H. Kijazi told media outlets Thursday the woman was attacked because "she was black and the incident had an element of racism", adding that Africans were routinely targeted in India.

Kijazi was set to meet the victims Friday evening together with a team of Indian foreign ministry officials.

Local authorities have dismissed claims that the attack was racially motivated, describing it as a case of "mistaken identity".

The management student said in a complaint lodged with police on Wednesday that the rioting mob attacked her car as they drove near the scene of the road accident less than an hour later.

"Our car was set ablaze. They tugged at my t-shirt and it tore, leaving me without anything. They continued to thrash us and we ran for our lives," she was quoted by the Times of India in her complaint as saying.

Police have come under fire for allegedly failing to stop the attack after the student said she pleaded with an officer for help, stressing that she was Tanzanian and knew nothing of the accident.

"He told us 'you all look alike and should get the black man who ran over a woman in the area'," she alleged in her complaint.

In 2014 in New Delhi, a mob attacked three African men in a metro station for apparently harassing local women, in what was branded a racially motivated incident.

Delhi's former law minister was also accused in 2014 of harassing African women after he led a vigilante mob through an area of the capital, accusing the women of being prostitutes.