Mexico's ambassador to the United States rejected a suggestion by Republican White House hopeful Rick Perry that US troops could be sent over the border to quell Mexico's escalating drug wars.

"The issue of participation, or the presence of, US troops on Mexican soil is not on the table," the ambassador, Arturo Sarukhan, told reporters on Monday.

Perry -- who is the governor of Texas, right on the US-Mexico border -- raised eyebrows over the weekend by suggesting Mexico's drug cartel woes might require US military assistance.

Perry, campaigning in New Hampshire, said Saturday that the two countries "can work together. Because there has been in my opinion a lack of trust.

"It may require our military in Mexico working in concert with them to kill these drug cartels and to keep them off of our border and to destroy their networks," Perry said.

"The way that we were able to stop the drug cartels in Colombia was with a coordinated effort."

Sarukhan said the idea of US troops on Mexican soil "is not a element of strategy that is being foreseen, not a part of the tremendously innovative ways in which Mexico and the United States have been using to fight transnational organized crime."

That has been Mexico's policy "for a very long time," he stressed.

The United States and Mexico cooperate on the anti-drug fight in multiple channels, mostly through information exchanges.

More than 41,000 people have been killed across Mexico since the federal government in 2006 launched a crackdown against drug cartels, according to official data and media tallies.