The subsidy, which fulfills one of Calderón´s campaign promises, will go to families registered for the Opportunities Program that provides education, food and health assistance.

The program will be retroactive to Jan. 1, the president said in a ceremony at Los Pinos, his official residence.

Calderón said the subsidy program would increase the assistance received by nearly 25 million poor Mexicans by 30 percent and represented a 10-percent hike in the budget of the Opportunities Program.

"By providing support for energy expenditures and freeing up family resources, they will have additional economic resources that can be destined for purposes that they themselves freely determine," the president said.

Calderón reiterated his commitment to channeling public spending to the sectors of society most in need of them, saying that "the eradication of extreme poverty is not just an obligation of our generation, it´s imperative for justice and prosperity in the country."

Since being sworn in on Dec. 1 for a six-year term, Calderón has taken a number of measures to fight poverty, including creating a program to support development in the 100 poorest municipalities.

The administration also launched "Health Caravans" to provide medical care to people in rural communities.