Mexican troops arrive along U.S. border

MEXICO CITY, Mexico (CNN) -- Helicopters were bringing 2,000 Mexican troops into the U.S.-Mexican border city of Juarez on Friday to quell a wave of drug-related violence blamed for 200 deaths since January, the city's mayor said.

"Two rival drug cartels tried to push each other out of the city," Jose Reyes Ferriz told CNN.

Among those killed were about 20 police officers representing the state, the military and the federal and city governments, he said.

"Many [people] say the drug cartels targeted specifically the heads of the police departments," he said.

"The violence got extremely bad in the city."

He said no uninvolved civilians have been injured.

"The two rival drug cartels in Mexico, one's from the Gulf, one's from the Pacific -- and Juarez being right down the middle, they tried to push the other one out of the area," he said. Watch police clash with suspected drug smugglers »

Juarez sits across the Rio Grande from El Paso, Texas. The majority of the troops will be based in the city.

Defense Secretary Guillermo Galvan said Thursday 2,026 soldiers, 180 military tactical vehicles, three airplanes and more than a dozen drug detection devices would be used in the military operation.

Mexican Attorney General Medina Mora stressed that the violence that goes along with drug trafficking is "not in any way a sign of strength, but a sign of weakness, deterioration and decomposition." E-mail to a friend

CNN's Ariel Crespo contributed to this report.

All About Mexico • Drug Trafficking