An improvised bomb spotted at the Gateway to the Americas International Bridge in Laredo has raised safety concerns among people who travel between the U.S. and Mexico.

The report of an improvised explosive device – or IED – found on February 4, was made public two weeks later. The Mexican Attorney General’s Office (PGR) released few details about the incident on their government website.

Vitelia Mejia often visits her daughter who lives across the border in Nuevo Laredo, Mexico. She can’t believe someone would dare leave a bomb on the bridge.

“It’s always been unsafe and we’ve always heard such things, but it usually ends up not being true,” Mejia said.

Luis Valtierra, 36, crosses the bridge into the U.S. two to three times a week. He lives on the Mexican side where he runs a business.

“It’s scary,” Valtierra said. “There’s hundreds of people who cross the bridge by foot.”

More than 250,000 pedestrians cross the Gateway Bridge every month.

The bomb was spotted on the Mexican side and was deactivated by Mexican law enforcement. Customs and Border Protection officials say that Laredo firefighters performed a sweep to ensure the safety of those on the bridge that day.

“We always have to be expecting the unexpected because all it takes is one time,” Congressman Henry Cuellar said.

U.S. Rep Cuellar wants to allocate more security resources at these border bridges.

“Imagine if there’s, god forbid, an explosion and it affects one bridge completely. That has an economic impact,” Congressman Cuellar said. “I will be sitting down with the [CBP] commissioner and ask him specifically, ‘What else can we do to address this issue and what can work with the Mexican side?’”

Mexican authorities are overseeing the investigation. It’s not yet clear who’s behind the IED or what the target was.

The report also revealed that Mexican law enforcement discovered two mines at the border town of Camargo, across from Rio Grande City, Texas.