WASHINGTON (CBS DC) — A top U.S. general in charge of protecting the country’s southern border says the constant flow of illegal immigrants, drugs and possible terror threats have created an “existential” threat to national security – one that border authorities are unable to combat.

Commander of U.S. Southern Command, Marine Corps Gen. John Kelly, says the influx of immigrants crossing into the have exposed U.S. border vulnerabilities and bring with them a vast network of illegal drugs, weapons and unaccompanied children. Gen. Kelly told Defense One that Congress has viewed pleas for border help with “low importance.”

“In comparison to other global threats, the near collapse of societies in the hemisphere with the associated drug and [undocumented immigrant] flow are frequently viewed to be of low importance,” Kelly told Defense One. “Many argue these threats are not existential and do not challenge our national security. I disagree.”

Kelly has asked Congress for increased financial aid, ships and drones to help combat the nearly 90,000 unaccompanied alien children (UAC) expected to cross the border before the end of the year. He told a Senate and House Armed Services Committee hearing members that budget cuts are “severely degrading” military capabilities to defend the southern U.S. border.

Kelly told congressional lawmakers that his task forces were unable to take action on almost 75 percent of illicit trafficking events: “I simply sit and watch it go by,” he said.

Kelly said that drug trafficking alone has created such a massive network of corruption that allows for possible terrorist threats and weapons to seep across the border.

“All this corruption and violence is directly or indirectly due to the insatiable U.S. demand for drugs, particularly cocaine, heroin and now methamphetamines,” Kelly told Defense One, “all of which are produced in Latin America and smuggled into the U.S. along an incredibly efficient network along which anything – hundreds of tons of drugs, people, terrorists, potentially weapons of mass destruction or children – can travel, so long as they can pay the fare.”

Kelly said that the unaccompanied children making the dangerous trip north are escaping Central American countries with some of the highest murder rates that are already “near-broken societies.”

“Although there are a number of other countries I work with in Latin America and the Caribbean that are going in the same direction, the so-called Northern Triangle (Guatemala, El Salvador and Honduras) is far and away the worst off.”