The Obama administration is trying to "mitigate" the outrage Arizona's new immigration law has caused in Mexico, and the issue will top the agenda during next month's visit to Washington by the country's leader, Secretary of State Hillary Rodham Clinton said on Thursday.

"Not surprisingly, the Mexican government has registered its very strong concern about the legislation passed in Arizona," Mrs. Clinton told reporters at the State Department. "We'll be working to understand and try to mitigate the concerns on that and other issues."

Mexican President Felipe Calderon is scheduled to arrive on a state visit in about three weeks, and until last week, U.S. officials expected the recent wave of violence along the U.S.-Mexican border to dominate the discussions.

That matter, however, is likely to be overshadowed by the Arizona law, which aims to crack down on illegal immigration by authorizing police to detain suspected illegal immigrants. Many of those immigrants in Arizona are believed to be Mexican.

President Obama and Homeland Security Secretary Janet Napolitano, a former Arizona governor, have voiced their opposition to the new law.

Also on Thursday, an Arizona police officer and a Latino group filed the first legal challenges against the new law. The officer's lawsuit, filed in U.S. District Court in Tucson, claims the law violates numerous constitutional rights and could hinder police investigations in mostly Hispanic areas, the Associated Press reported.