The city of Matamoros sits tantalisingly close to the US border, with Brownville, Texas in clear view over the Gateway International Bridge.

It was here that the Salvadoran refugee Oscar Alberto Martinez Ramirez, 25, and his 23-month-old daughter, Valeria, arrived to claim asylum in the United States.

But on Monday, their drowned bodies were found locked in a final embrace, Valeria tangled up in her father’s black t-shirt, on the banks of the Rio Grande river, which runs under the bridge.

The shocking photograph of their corpses, now broadcast around the world, illustrates the plight of migrants and refugees who are making increasingly perilous attempts to reach the United States.

But the story of what drove them to attempt the fatal river crossing also raises questions about the Trump administration’s border regime, which is turning refugees away from the border or cramming them into purgatorial reception centres.

From the scorching Sonoran Desert to the fast-moving Rio Grande, the 2,000-mile border has long been a deadly crossing between ports of entry. A total of 283 migrant deaths were recorded last year; the toll so far this year has already reached 170.