“You never get used to it. I leave my house afraid. I come home afraid,” a resident of Soyapango, El Salvador, said furtively.

He knows that in the second most dangerous country in the world, even wearing the wrong colour trainers can get you murdered by MS-13, the vicious international gang that has terrorised Salvadoran citizens for more than 20 years.

Donald Trump, the US president, has promised to crush the gang, which is blamed for dozens of macabre killings around the US.

Yet his decision last week to end Temporary Protected Status (TPS) for 200,000 Salvadoran immigrants could both empower the group in El Salvador and provide a new generation of recruits in the US, according to experts in immigration and gang violence.

Charles Call, an associate professor of international peace and conflict resolution at American University, said: "I think the large number of Salvadorans who are going back to their country will be prime recruiting ground for MS-13 and will make the security situation in El Salvador worse.