Volunteers handed out pizza to El Paso residents who were waiting to give blood after a mass shooting which killed 20 people and injured dozens more.
Hundreds flocked to local donation centres around the city after an appeal from the police department.
The response was so strong that blood bank staff were forced to turn people away, asking them to schedule an appointment later in the week.
One kind stranger was spotted handing out the pizza outside Vitalant in West El Paso on Saturday.
Elsewhere, volunteers also handed out water and other drinks to those waiting in the queue.
The attack, which took place in a shopping centre, killed 20 people and injured 26.
A 21-year-old man, named as Patrick Crusius, is in custody. Police said he is from the city of Allen, near Dallas.
El Paso County District Attorney Jaime Esparza said the suspect has been charged with capital murder.
US Attorney John Bash said he is working with authorities in bringing federal hate crimes charges and federal firearms charges, which would carry the death penalty against the suspect.
"We are treating it as a domestic terrorism case, and weâre gonna do what we do to terrorists in this country, which is deliver swift and certain justice," Mr Bash said.
Hours after the latest shooting, nine were killed and 24 injured when a gunman opened fire at a bar in Ohio.
The shootings came less than a week after a 19-year-old gunman killed three people and injured 13 others at a popular garlic festival in California.
