Napolitano's comment was the latest riposte in politically charged exchanges between Texas' Republican governor and President Barack Obama's administration dating back to Perry's call for 1,000 federally paid National Guard troops 20 months ago.

Perry's office has said spillover drug cartel violence along the border is a persistent threat to Texans and Obama's administration should pay for protection.

Obama ordered 250 National Guard troops to the Texas border at federal expense in August as part of an emergency call-up of 1,200 troops along the U.S.-Mexico border.

Perry spokeswoman Katherine Cesinger said the stepped-up border security measures have been "grossly insufficient," particularly since border security and homeland security remain federal responsibilities.

"As a former border governor, Secretary Napolitano knows how greatly unjust it is for this administration to pass the cost and burden of keeping the entire nation safe on to the taxpayers of Texas," she said.

Resisting call for troops

Gangland battles continue unabated in Ciudad Juarez across from El Paso, but they also have escalated dramatically in the states of Tamaulipas and Nuevo Leon along Texas' southeast border.

The administration has resisted calls for additional troops, citing a $600 million buildup of federal law enforcement personnel and technology already committed in response to Mexican drug wars along the border.

"We have been putting resources into the border at an unprecedented rate," Napolitano said Friday.

The Obama administration is "paying particular attention" to border communities concerned about spillover violence, she emphasized.

But neither the U.S. Border Patrol and Customs and Border Protection nor local county sheriffs are seeing signs of violence threatening U.S. border communities, as some Republican politicians claim, Napolitano said.

Insufficient resources

National Guard troops are being deployed where they are needed and "if that need changes, they will be moved," Napolitano said.

Perry, she said, can call up the National Guard in Texas if he wants to pay for it: "That's always an option available to a governor," she said.

Perry has criticized the administration for giving Texas only 20 percent of the federally paid National Guard troops along the southwest border when the state's border accounts for 64 percent of the 1,969-mile border.

"I don't need a Washington briefing to tell me that the car bombs going off across the Rio Grande, the cartels recruiting teenage Texans as hit men and bullets from shootouts hitting UT-Brownsville and El Paso's City Hall are signs that things are going from bad to worse," Perry told the National Guard Association Convention last month. "America needs swift action and sufficient resources to protect our border communities and the families who call them home."

Perry, as commander in chief of the Texas National Guard, activated 48 troops, two Blackhawk helicopters and 10 high-clearance military vehicles at state expense in early September to support search-and-rescue efforts after flooding from the remnants of Tropical Storm Hermine.

stewart.powell@chron.com