Mexico City - President Obama's executive action on gun control may have reenergized a polarizing debate in the US, but it offered cautious hope in Mexico last week.

Hundreds of thousands of legally purchased and illegally transported guns move from the US into Mexico each year, according to both governments, and make up the majority of firearms confiscated from crime scenes here.

Analysts say the expansion of background checks could disrupt the flow of trafficked guns that play a central role in drug trafficking and the overall homicide rate. More than half of the nearly 20,000 homicides in 2014 were due to gun violence, according to national statistics agency INEGI.

Just how many US guns find their way into Mexico is difficult to pinpoint, but the US Bureau of Alcohol, Tobacco, Firearms, and Explosives estimates that roughly 70 percent of illegal guns here originate in the US, while the Mexican military has put that figure closer to 90 percent. One 2013 academic study published in the journal of Economic Geography found that nearly 213,000 US guns funnel into Mexico each year.

"It may be coming from a national agenda, but it will have positive consequences for Mexico," says Javier Oliva Posada, a political scientist from the National Autonomous University in Mexico. "One measure won't solve everything, but it's certainly a step in the right direction" when it comes to US-purchased guns smuggled south of the border.

Expanding background checks to gun shows and online sales, as well as overhauling the overall system to include data across jurisdictions, could diminish the ease with which guns are pushed across the border. Straw buyers - people who legally buy guns in the US before handing them off to individuals who might have a criminal record prohibiting them from purchasing a gun - could find their operations more difficult, as could those who intentionally purchase weapons from sources who in the past weren't required to run checks on criminal records.

To Maureen Meyer, a Mexico specialist at the Washington Office on Latin America, the move represents an important first step. "If they are assigning additional ATF agents and expanding their ability to investigate, and expanding background checks, that could limit the possibility of traffickers or organized criminals going to gun expos or unlicensed dealers in the US ... [and] could expand the possibility of taking down networks into Mexico."