An evangelical pastor has told of his past as a member of the world's most dangerous gang and why he is ministering to gang members today. 

William Arias, from El Salvador, grew up in a poor family and was recruited into the MS-13 gang as a 10-year-old.

MS-13 is an international criminal gang that originated in Los Angeles in the 1980s. It uses extreme violence to enforce its authority and is involved in drugs, prostitution and every kind of organised crime. Members are fiercely loyal to each other, communicating via secret hand signs and marked by gang tattoos.

President Trump has vowed to tackle the gang, describing its members as 'animals'.

Arias told the BBC how he was addicted to marijuana and glue by the age of seven and was drawn in to gang life by friends.

'They told me there were women, drugs, alcohol , fun all the drugs and drink you could want,' he said.

'I had a lot of friends who drew me in and showed me how to make the gang's hand signs, who called me their homeboy, who said they'd never give up on me.'

He carried out revenge killings and murders, the hallmark of MS-13, and his relationship with his family broke down.

'At home they hardly recognised me,' he said.

He became a local leader and said the gang was 'burned into my heart'. ' I would have sacrificed my life for one of my homeboys,' he said.

He was caught and served three years in jail, but became disllusioned with the gang. 'They never visited me, they were nowhere to be seen. Only my mother came to see me and stayed by my side, even though I had disrespected her and told her she wasn't part of my family,' he said.

After his release he became a pastor and has devoted his life to repairing some of the harm he has done.

'When I joined this path of God there were those who told me, you won't last six months, because not even God loves gang members,' he said.

He deeply regrets the harm he has done by recruiting children into MS-13, some of whom died, and believes God has called him to serve them.

'In the gang, there are only three paths,' he said. 'That's why gang members sometimes get tattoos of three dots. People think they stand for sex, drugs and rock 'n roll, the crazy life of the gang. But in fact they stand for prison, hospital or death.'

So, says Arias: 'I can't stay with my arms folded, watching them die or rot in prison. God pushes me to do something for them.'