A Texas border rancher was killed near the border by a suspected cartel IED earlier this month, the Texas Department of Agriculture told The Post Tuesday — as officials issued an urgent safety warning for the Rio Grande Valley.

Rancher Antonio Céspedes Saldierna, 74, who worked on both sides of the border, along with Horacio Lopez Peña, were killed in the blast in Tamaulipas, Mexico, which was just south of Brownsville, Texas. Lopez’s wife, Ninfa Griselda Ortega, was hospitalized with injuries.

Saldierna was driving on his ranch when he hit the explosive device, causing it to detonate, according to KRGV.

Texas Agriculture Commissioner Sid Miller said the deadly explosion is part of a “growing threat posed by cartel activity along our southern border” and encourages ranchers “to exercise extreme caution” in the area.

“I encourage everyone in the agricultural industry to stay vigilant, remain aware of their surroundings, and report any suspicious activity to law enforcement. Additionally, you can avoid dirt roads and remote areas, refrain from touching unfamiliar objects that could be explosive devices, limit travel to daylight hours, stay on main roads, and avoid cartel-controlled regions,” said Miller.

Saldierna’s son Ramiro Céspedes, a US Army veteran who was injured by an IED during a deployment, was shocked to learn of his father’s killing back home.

“I consider this a terrorist attack because if I went to war to fight terrorists, and I’m seeing the same thing here to me – my personal opinion – it is a terrorist attack,” Ramiro said.

Border agents have received warnings about increased threats from cartels and the Trump administration has responded by designating some of them as foreign terrorist organizations.