Mexican authorities have found the charred remains of 21 people in the state of Tamaulipas on the border with the United States, NDTV reported.
The burned bodies, presumably victims of a battle between drug cartels, were found next to seven burnt cars near the border town of Ciudad Miguel Aleman, about 270 kilometres (170 miles) from McAllen, Texas, a city Donald Trump was due to visit.
According to state police spokesman Luis Rodriguez, it is believed that gunmen from the Gulf Cartel had fought with members of the Northeast Cartel.
Tens of thousands of people have been killed in Mexico during last years of fighting among cartels and between the criminals and security forces. The cartels vie for control of drug trafficking and extortion rackets and have been known to exploit migrants.
Since deployed the army to crack down on drug cartels in 2006, more than 200,000 people have been murdered in related violence; 28,711 were slain in 2017, a grim record which preliminary estimates indicate was beaten in 2018. For comparison's sake, the number of murders in the US, which is far more populous, was 17,284 in 2017, according to FBI data.