By DINA CAPPIELLO
Associated Press
WASHINGTON
The Obama administration's top environmental official in the oil-rich South and Southwest region has resigned after Republicans targeted him over remarks made two years ago when he used the word "crucify" to describe his approach to enforcement.

In a letter to EPA Administrator Lisa Jackson sent Sunday, Al Armendariz says he regrets his words and stresses that they do not reflect his work as administrator of the five-state region including Texas, New Mexico, Oklahoma, Arkansas and Louisiana.

Republicans in Congress had called for Armendariz' firing, after Oklahoma Sen. James Inhofe highlighted the May 2010 speech last week as proof of what he refers to as EPA's assault on energy, particularly the technique of hydraulic fracturing, or fracking.

Several disputed contamination cases in Texas have helped stoke environmental concerns over fracking.