Two French teenagers have admitted strangling an 11-year-old boy to death after accusing him of stealing £9 worth of fishing gear.

The victim, named only as Théo, was found dead on the banks of the Vilaine River in Rennes, western France, on Sunday afternoon.

A 15-year-old girl and a 16-year-old boy are in custody and due to appear before a judge on Wednesday, local media reported.

According to prosecutors, the pair told investigators they wanted revenge on Théo because they believed he had stolen fishing equipment from them, writes Le Parisien.

The gear was reportedly worth around ten euros (£9).

Théo was found lifeless after a fisherman alerted emergency services after hearing a child screaming nearby.

When police arrived around 10 minutes later, they discovered the boy in a wooded area close to the water.

He was lying in bushes with a wet bath towel tied tightly around his neck, French broadcaster BFMTV reported.

Paramedics attempted first aid but Théo died at the scene.

An autopsy later confirmed he died from asphyxiation.

Investigators believe the 11-year-old had been fishing on the banks of the Vilaine earlier that afternoon with the two teenage suspects.

The 16-year-old boy and Théo had reportedly known each other for just one day after meeting while fishing and arranging to see each other again the following day.

It is unclear whether Théo knew the 15-year-old girl.

After the attack, the two teenagers were reportedly seen running from the scene, according to public prosecutor Frédéric Teillet.

Police later found Théo's fishing equipment at the suspects' homes during searches.

The pair were not previously known to police or judicial authorities and are said to attend the same school.

According to the state prosecutor, the teenagers told investigators they strangled the child in revenge and partly to recover fishing equipment they believed he had taken.

Théo had told his parents on Saturday that the 16-year-old boy had used bait to lure him, according to reports.

French police opened a murder investigation after the discovery of the boy's body on Sunday.

'As we suspect that a third party is involved in the incident, we have opened an investigation into the murder of a minor child,' prosecutor Frédéric Teillet said in a statement on Monday.

The case has been handed to DCOS, the Department for Organized and Specialized Crime.

Police investigators worked through the night at the scene after the discovery, with a large stretch of the riverbank cordoned off while forensic teams gathered evidence.