PHOENIX (Reuters) - A solid majority of Americans back Arizona’s tough crackdown on illegal immigrants, while just 25 percent support President Barack Obama’s immigration policy which includes legalizing millions of unauthorized migrants, a study found on Wednesday.

The controversial Arizona law passed last month requires state and local police, after making “lawful contact,” to check the immigration status of anyone they reasonably suspect is in the country illegally, and arrest those who cannot prove it.

The report by the Pew Research Center for the People and the Press (www.people-press.org) found that 59 percent of adults polled in a national survey gave their overall approval to the law, which opponents charge is unconstitutional and a mandate for racial profiling.

Seventy-three percent said they backed a measure requiring people to produce documents verifying their legal status if police ask for them, while 67 percent approve of allowing police to detain anyone who cannot verify that they are in the country legally.

The new law has pushed a debate over immigration to the fore in U.S. politics, and rebooted a drive by Obama and Senate Democrats to overhaul federal immigration laws -- although it is seen as a longshot before November congressional elections.

Obama supports a system allowing undocumented immigrants in good standing to pay a fine, learn English and become citizens. He also backs tightening border security and clamping down on employers that hire undocumented workers.

The survey, carried out among 994 adults -- found that only 25 percent supported Obama’s handling of immigration policy, while more than twice as many -- 54 percent -- said they disapproved.

It found that Democrats are evenly split over the Arizona law -- which is set to come into effect at the end of July -- with 45 percent backing it and 46 percent saying they disapprove of it.

The measure, signed into law by Arizona’s Republican Governor Jan Brewer on April 23, has triggered an international furor and unleashed legal challenges and calls for an economic boycott of the Grand Canyon state.

On Tuesday, United Nations human rights experts added their voices to criticism of the law, saying it may lead to police targeting people on the basis of ethnic origin, in violation of international law.