A Central American migrant carries a child after a Border Patrol sprayed them while trying to cross the US-Mexico border. Guillermo Arias/AFP

MEXICO CITY: Mexican police and federal officials on Saturday detained 107 Central American migrants seeking to enter the United States in the border city of Reynosa, the government of the northeastern state of Tamaulipas said.

Following a tip-off, state police intercepted a group of migrants who had been taken out of trucks in a western part of the city, which lies across the border from McAllen, Texas.

At the scene, unidentified gunmen began shooting at police, and one of the attackers was killed in the ensuing exchange of fire, the Tamaulipas government said in a statement.

The statement said police seized a firearm and cartridges but did not provide details on whether any gunmen were arrested or who they were.

Separately, police discovered a group of Central American men and women on the edge of a highway in Reynosa. They called in federal migration officials, who are now reviewing the legal status of the Central Americans detained, the government said.

The National Migration Institute counted 51 Guatemalans, 47 Hondurans and 9 Salvadorans detained in total, it added.

Mexico's new government has pledged to regulate and stem the flows of people moving from Central America to its northern border as it seeks to reduce tensions with US President Donald Trump over illegal immigration into the United States.

Reuters