President Obama said today that the federal government will monitor Arizona's tough new state measure on immigration that he said "threatens to undermine basic notions of fairness that we cherish as Americans."

Speaking at a Rose Garden ceremony, Obama said the bill, which Gov. Jan Brewer must decide today whether to act upon, could also undercut trust between police and local communities.

The sweeping measure would make it a crime under state law to be in the country illegally. It would also require local police officers to question people about their immigration status if there is reason to suspect they are illegal.

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Update at 10:46 a.m. ET: Obama called on Congress to take up a new federal immigration bill:

Our failure to act responsibly at the federal level will only open the door to irresponsibility by others, that includes, for example, recent efforts in Arizona which threaten to undermine basic notions of fairness which we cherish as Americans, as well as the trust between police and their community that is so crucial to keeping us safe.

He added: "If we continue to fail to act at the federal level, we will continue to see misguided efforts opening up around the country."

Obama said he has called upon his administration to monitor the Arizona efforts for any civil rights and other implications.

Update at 1:46 p.m. ET: Gov. Brewer blames the Obama administration for leaving Arizona no choice but to get tough on immigration, the East Valley Tribune reports.

She tells a press conference at the state's National Guard headquarters, the newspaper reports, that it is not the job of state government to secure the border "but we have no other choice.''

"Those who have failed to protect us have shown only weakness and delay,'' she says, adding that top administration officials have "simply turned a blind eye to the issues that Arizona is being overrun by illegal immigration, terrorizing the citizens.''

"No matter the cost, no matter the sacrifice, we cannot shirk government's principle responsibilities to the citizens we serve to provide safety and security,'' she says.

Update at 2:30 p.m. ET: Gov. Brewer has scheduled a news conference today at 4:30 p.m. ET on the pending legislation.

(Posted by Doug Stanglin)