Ciudad Juárez, Mexico - US law enforcement agents carried out exercises using barbed wire and concrete blocks Friday at a crossing on with as tensions crept up ahead of President-elect 's inauguration.

US law enforcement agents carried out exercises using barbed wire and concrete blocks Friday at a crossing on the border with Mexico as tensions crept up ahead of President-elect Donald Trump's inauguration. © HERIKA MARTINEZ / AFP

Vehicle crossings on an international bridge connecting Ciudad Juarez and El Paso, Texas were halted for about 40 minutes while US Customs and Border Protection (CBP) officers carried out training, an AFP journalist said.

According to the CBP office in El Paso, the exercises began in 2019 and aim to ensure that agents are prepared for potential border incidents.

Residents in Ciudad Juarez said the exercises have multiplied as Trump prepares to take office on Monday, having vowed of undocumented migrants in the history of the US.

"This is the second closure I've seen this week," said Yadira Martinez, who was among those trying to cross.

Ciudad Juarez is one of the main gateways to the US for migrants fleeing poverty, violence, or political instability in their countries.

It is also one of the official entry points for migrants with appointments to file an asylum application through the US government's cellphone app CBP One.

Earlier this week another Mexican border city, Tijuana, declared an emergency to free up funds to deal with the potential arrival of deportees.

US Customs and Border Protection officers conduct a mobile field force training exercise at Paso del Norte-Santa Fe international bridge in Ciudad Juarez, Chihuahua state, Mexico on Friday. © HERIKA MARTINEZ / AFP

Trump, who repeatedly called the arrival of migrants an "invasion," has promised to declare at the border with Mexico after taking office and to expel millions who lack residency papers.