"The rank and file are starving, just like their population," Admiral Craig Faller, who heads the US military's Southern Command, told the Senate Armed Services Committee.

He called the Venezuelan military a "degraded force," but one that "remains loyal to Maduro -- and that makes it dangerous."

Faller, who assumed command of SOUTHCOM in November, said the US military was keeping a close eye on Venezuela and was prepared to protect American personnel and diplomatic facilities "if necessary."

Though President Donald Trump has declined to rule out military intervention in crisis-gripped Venezuela, Faller said the focus is on supporting diplomatic efforts.

He said the United States is looking for signs the Venezuelan military's loyalty to Maduro might be "cracking," but he declined to elaborate in the public hearing.

International pressure is intensifying on Maduro to step aside and support is growing for his opposition rival Juan Guaido, who has so far been recognized by around 40 countries since declaring himself interim president on January 23.

Faller said he had visited the Colombia-Venezuela border, where US troops deployed on the USNS Comfort medical ship are operating medical camps.

In an apparent reference to enlisted Venezuelan soldiers, he said he had seen "kids" who had lost as much as 30 pounds (13.5 kilos) in the space of a year.

"They are stick thin, they'd never had medical attention, we think that condition affects a large swath of the population and we think that population's ready for a new leader," Faller said.

Food and medicine shortages have pushed 2.3 million people to flee Venezuela since 2015.