PHOENIX (AP) — Republican Sen. John McCain of Arizona says it's possible some of the more than 2,000 illegal immigrants recently released by the Homeland Security Department because of budget cuts had been convicted of serious crimes.

McCain sent a letter to Homeland Security Secretary Janet Napolitano on Friday demanding information on the release of the detainees, who were facing deportation. He says there's a possibility some of them had committed serious crimes such as smuggling, narcotics trafficking and child molestation.

Federal officials maintain those released were "noncriminals" and low-risk offenders.

McCain wants Napolitano to make public this month the criteria used to determine which detainees were released and how many had been convicted of serious crimes.

The states where immigrants were released include Arizona, California, Georgia and Texas.

McCain is heading a Republican effort to craft immigration legislation focused on border security.