Representatives of 44 African countries accused the Indian government on Monday of failing to do enough to stop racist attacks on their nationals following a series of brutal assaults targeting Nigerians.

Around a dozen people were injured, some seriously, when a mob angered by the death of a local teenager went on the rampage in a satellite city of New Delhi last Monday.

The violence erupted after a group of Nigerian students who were detained in connection with the teen's death were released without charge, with police saying there was no evidence against them.

The vicious assault was captured on camera and shared widely on social media, triggering concern over a rise in racist violence against Africans in India.

Read more: Indian police arrest five over attack on Africans

In a statement, the African Heads of Mission said that "no known, sufficient and visible deterring measures were taken" by New Delhi after previous such attacks.

It said the authorities had failed to "sufficiently condemn" either the latest attacks or past incidences of racist violence against Africans.

The diplomats also called for an independent investigation into the latest violence by groups including the UN's Human Rights Council, calling it "xenophobic and racial".

Also read: Mr Modi’s African chromosomes

Thousands of people from African countries study and work in India, where many face discrimination. They are often accused of involvement in the illegal drug trade.

The issue was thrown into the spotlight last year when a Congolese teacher was bludgeoned to death allegedly by three Indian men after an argument over hiring an auto-rickshaw in Delhi.

In 2013, a Nigerian national was killed by a mob in the tourist state of Goa, with a state minister later calling Nigerians a "cancer".

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, claiming they were prostitutes.

Police have arrested six of the 10 main suspects involved in the latest attack.

India's foreign ministry condemned the incident as "deplorable" and assured Nigeria steps were being taken to protect their citizens in India, as Abuja demanded "diligent prosecution" of the culprits.