A line of Mexican National Guard and Army trucks rumbled along the border separating Ciudad Juárez and El Paso, Texas Wednesday, among the first of 10,000 officers Mexico has sent to its northern frontier following tariff threats by President Donald Trump.

National Guard troops near Ciudad Juárez removed ladders and ropes from border trenches, with patrols also spotted in other areas near Tijuana.

There is anxiousness and uncertainty of what exactly the new tariffs will be and how they could impact the economy of El Paso-Juárez Borderland, which relies on trade between the neighboring nations. Mexico is the largest international trading partner for the United States and the state of Texas.