Judge blocks Alabama immigration law to buy time

BIRMINGHAM, Ala (Reuters) - A federal judge on Monday blocked Alabama's tough new immigration law from taking effect this week, making it the latest U.S. state to have a measure on illegal immigration halted in court.

Chief U.S. District Judge Sharon Lovelace Blackburn cited the need for more time to consider the legal challenges against the law in an injunction that blocks implementation of the law through September 29.

"In entering this order the court specifically notes that it is in no way addressing the merits of the motions," the judge wrote in her two-page order.

Federal judges have previously blocked key parts of other immigration laws passed in Georgia, Arizona, Utah and Indiana.

The Alabama law, widely seen as the toughest state measure on illegal immigration, requires police to detain people they suspect of being in the United States illegally if they cannot produce proper documentation when stopped for any reason.

The law also makes it a crime to knowingly transport or harbor an illegal immigrant, and requires public schools to determine, by reviewing birth certificates or sworn affidavits, the legal residency status of students upon enrollment.

Lawyers for the Obama administration and other groups asked the judge last week to halt the law, which was set to take effect this Thursday.

The administration argued that the U.S. Constitution bars states from adopting their own immigration regime that interferes with the federal system. Other opponents say the law will deter children in immigrant families from enrolling in school and criminalize Alabama residents who interact with those in the country without documents.

Conservatives have complained that President Barack Obama has failed to sufficiently stem the flow of illegal immigrants into the United States. The Obama administration successfully sued to block Arizona's tough law last year.

Attempts to overhaul federal immigration policy have gone nowhere in the U.S. Congress.

(Writing by Colleen Jenkins; Editing by Jerry Norton and Cynthia Johnston)