The general praised Mexican efforts, but said the US needed to do more
The US is drawing up comprehensive plans to help Mexico in its fight against drug-trafficking, a senior military official has told Congress.
Gen Gene Renuart, head of the US Northern Command, told a Senate hearing that troops or anti-narcotics agents would be sent to the Mexican border.
The plan could be finalised as early as this week, he added.
Correspondents say Mexico's mounting drug violence has emerged as a real national security threat to the US.
"Certainly, there may be a need for additional manpower," said Gen Renuart, who oversees US military interests in the border region.
"Whether that is best suited or best provided by National Guard or additional law enforcement agencies, I think, this planning team will really lead us to," he told the Senate Armed Services Committee.
Governors of states that border Mexico have expressed concern both about the cartels, whose main source of income is exporting drugs such as cocaine into the US, and at the prospect of effectively militarising the US-Mexico frontier.
Over 1,000 Mexicans have died in drug-related violence so far this year.
The military is already employing border security techniques mastered in the war zones of Iraq and Afghanistan, including unmanned aerial vehicles and technology capable of locating underground tunnels, reports say.
But an inter-agency government team, meeting this week at the Department of Homeland Security, is now expected to produce a broad new initiative to confront a drug war that has killed thousands in Mexico and spilled over into US cities.
"I think we'll have good plans come out of this work this week," Gen Renuart told the hearing.
A separate Senate committee in Washington heard that the presence of the Mexican drug cartels in the US had more than quadrupled since 2006.
The news came as Mexico and the US remained locked in a trade dispute centred on their busy border.
The US government stopped a pilot scheme earlier this month which allowed Mexican trucks to use roads in the US.
Mexico said the decision violated a free-trade deal between the countries and says it will impose tariffs on a range of American exports.