U.S. Customs and Border Protection officers established random checkpoints along the Tijuana-San Diego border and arrested departing Mexicans who lack proper identification papers, the Los Angeles Times said Wednesday.

"If our officers come upon people who are here illegally . . . regardless of whether they're leaving the country, we detain them, make a record of the fact they were here illegally and return them to Mexico," customs agency spokesman Vincent Bond told the Times.

Republican lawmakers and groups seeking tougher immigration measures praise the arrests as a needed crackdown on drug trafficking and other criminal behavior.

"Whether people are coming or going . . . checkpoints are just another line of defense that targets illegal behavior," a spokesman for U.S. Rep. Duncan Hunter, R-Calif., said.

Rights groups say the policy of arresting illegal immigrants returning to their country of origin is counterintuitive.