The U.S. Department of Homeland Security began a special program this week to repatriate illegal Mexican immigrants on airline flights to central Mexico from the Arizona border. The program has the support of the Mexican government, but some critics say it is too expensive. As reports from Houston, the repatriation flights are part of an overall strategy to reduce illegal crossings and deaths on the border.

The planes fly every day from the southern Arizona city of Tucson to Mexico City and Guadalajara, both of which are more than 1,500 kilometers to the southeast. From those cities, immigrants travel on buses back to their home towns. All travel expenses, including the chartered flights, are paid by the U.S. government, leading to some questions about the cost effectiveness of the program. Tucson Sector Border Patrol spokesman Rob Daniels says this is an experiment that will continue until the end of September when it will be evaluated.

"What we will do is, for the time being, operate one flight a day, leaving Tucson for Mexico City at midday. We have the ability to bring up to 150 illegal immigrants back to Mexico on each of these flights," he said.

Part of the idea is to move immigrants far into the interior of Mexico so as to discourage them from trying to cross the border again. In many cases immigrants who are repatriated at border crossings end up being apprehended again within a matter of days. But the immigrants themselves must volunteer for the flights and must make their request to the Mexican consulate in Tucson. If not,they are repatriaed at the border. Mr. Daniels says this program is based on an agreement between the United States and Mexico.

"A Mexican airline has been contracted by the U.S. government to carry the migrants back to Mexico and the program is done with the full cooperation of the Mexican government," he said.

The Arizona/Mexico is border area has become the main entry point for illegal aliens and drug smugglers in recent years. Much of the border region in the Tucson sector is dry, hot desert where Border Patrol agents are spread out over vast distances. Each year hundreds of migrants die trying to cross this desolate area.

Rob Daniels says the repatriation flights compliment the major effort announced two months ago to bolster enforcement at the border. He says this has resulted in stepped up detentions of illegal immigrants who can now be more easily detected by ground sensors, Border Patrol camera installations and unmanned aerial vehicles flying over the border. Mr. Daniels says these devices also give the Border Patrol the ability to more rapidly detect migrants in distress and send rescue teams to them.

"We have been able to save a number of lives, in excess of 300, and we still have the rest of July, August and September to go," he said.

At the end of September, the hottest driest season in the Arizona/Mexico border area will be over and the U.S. government's fiscal year will also be at an end. At that time, Mr. Daniels says, officials from both the United States and Mexico will evaluate the repatriation flight program and decide if it should be continued.