NEW DELHI (AFP) - India's federal investigators will take over the probe into the alleged gang rape and murder of a teenager that has sparked nationwide outrage and days of protests.

The 19-year-old woman from the marginalised Dalit community was attacked in mid-September in northern Uttar Pradesh state and died last Tuesday (Sept 29), in the latest case highlighting India's epidemic of sexual violence.

Five senior police officers have already been suspended over the investigation amid criticism of law enforcement's actions - including the cremation of the woman's body in the middle of the night against the wishes of her family.

The Chief Minister of the state - India's most populous with 200 million people - announced the decision to transfer the probe to the Central Bureau of Investigation late on Saturday.

"We are committed to giving the strictest punishment to the people responsible for this incident," Mr Yogi Adityanath, who is from the ruling Bharatiya Janata Party (BJP), wrote on Twitter.

The police have arrested four high-caste men on the charges of gang rape and murder.

Local authorities barricaded the village after the cremation to block opposition politicians and media from meeting the victim's family.

The decision was reversed on Saturday after widespread criticism.

The involvement of leaders of the opposition Congress party, Ms Priyanka and Mr Rahul Gandhi, in several demonstrations has sparked accusations from the BJP that they were politicising the issue.

The young woman's death comes months after four men were hanged for the 2012 gang rape and murder of a student on a bus in New Delhi, in a case that shook the nation.

An average of nearly 90 rapes were reported in India every day last year, according to data by the National Crime Records Bureau, but large numbers are thought to go unreported.

India's 200 million marginalised Dalits have long faced discrimination, and campaigners say attacks have increased during the coronavirus pandemic.