Reuters Summit-Mexican troops needed in drug war-US border czar

(For other news from the Reuters Latin American Investment Summit, click here)

* Bersin says Mexican troops needed at border for now

* Military not permanent solution in drug wars

By Tabassum Zakaria

WASHINGTON, May 8 (Reuters) - Mexico needs its army to lead the drugs war until its police forces are strengthened and able to tackle the violent gangs that pose a security threat on both sides of the border, the new U.S. border czar said on Friday.

He said the deployment of thousands of Mexican troops against drug cartels is not a permanent solution, but has helped curb a surge in violence along the border.

"This is an extraordinary situation, it's a national security situation that affects both sides," Alan Bersin, special representative for border affairs at the Department of Homeland Security, said at the Reuters Latin American Investment Summit in Washington.

Mexican President Felipe Calderon has sent tens of thousands of troops to fight the cartels since he took office in late 2006, relying on the military because so many police are on the payroll of the drug lords.

More than 6,000 people were killed in drug violence in Mexico last year, and U.S. officials fear that turf wars between rival gangs could spill across the border into the United States.

When the violence threatened to spin out of control in the border city of Ciudad Juarez, Calderon sent in an extra 10,000 troops and federal police in early March and they have had some success in calming things down.

Bersin said the army should stay involved "as long as it is necessary to prevent the violence from claiming the lives at the rate that it was" and to allow the Mexican government to strengthen its police forces.

"That's going to take some time," he said, although he added it should not require "many many years" and that he was optimistic that improved cooperation between Mexican and U.S. security forces would help stem the violence over time.

"This is a period, it's not going to last forever. Hopeful signs are that for the first time in border history we see an acceptance and co-responsibility by both sides of the border," he said.

Mexico's attorney general, Eduardo Medina Mora, told Reuters this week that the army presence in Ciudad Juarez had broken close collaboration between corrupt municipal police and drug gangs but he would not say how long troops would stay.

The central role of Mexico's army in the drugs war has raised concerns that it too could be corrupted, as well as allegations that troops are violating human rights.

Bersin, who served in a similar role in President Bill Clinton's administration, played down the risk of drug gangs gaining control of Mexican army units and said the level of cooperation between the U.S. and Mexican governments is unprecedented.

"The kind of candor and the range of potential cooperation is completely different from the past." (For summit blog: blogs.reuters.com/summits/)