** ADVANCE FOR SUNDAY, DEC. 31 **A National Guard soldier peers over the vast Otay Mountain Valley as he assists the Border Patrol infrared scope unit as agents search the area for smugglers in San Diego Wednesday, Dec. 20, 2006. The unit directs other agents in the area when they sight smugglers bringing illegal immigrants into the country. (AP Photo/Lenny Ignelzi)
An earlier version of this report incorrectly stated that Arizona had received a response to its request for National Guard troops. However, the White House said it has not decided where along the southwest border the troops will be deployed. NBC DFW regrets the error.
National Guard troops will be headed to the U.S.-Mexico border, but Texas is still waiting for an official answer to its request for help.
President Barack Obama has agreed to send 1,200 National Guard troops to the U.S. border with Mexico. The White House said it has not decided where along the Southwest border, which includes parts of California, Arizona, New Mexico and Texas, the troops will be deployed.
Almost a year and a half after the first letter was sent, Perry hasn't received an answer.
"We've not received approval (or denial) regarding Gov. Perry's request," said Perry's spokeswoman, Katherine Cesinger, in an e-mail. "But we remain hopeful that the federal government will provide the resources we've requested, including 1,000 Title 32 National Guardsmen, to secure the Texas-Mexico border."
A spokesperson at the Department of Defense said he couldn't give more information on the status of Perry's request.
More than 300 National Guard personnel are already on the U.S.-Mexico border engaged in counternarcotics missions.
NBC DFW's Lita Beck contributed to this report.