U.S. Republican presidential candidate Mitt Romney on Thursday softened his tone on immigration in a speech to the Hispanic community, offering what he called a strategy for "bipartisan and long-term immigration reform."

"Immigration reform is not just a moral imperative, but an economic necessity as well," Romney said to the National Association of Latino Elected and Appointed Officials' annual conference in Lake Buena Vista, Florida. "We can find common ground here, and we must. We owe it to ourselves as Americans to ensure that our country remains a land of opportunity -- both for those who were born here and for those who share our values, respect our laws, and want to come to our shores."

Romney also unveiled a series of family-friendly proposals aimed at immigrants who are current legal U.S. residents, but gave no details on how he would implement long-term reform if he is elected president, or suggested any remedy for the more than 11 million undocumented immigrants. During the Republican primaries, he said the solution was for illegal immigrants to stop working and leave the country, which he termed "self-deportation".

Romney refused to say whether he would overturn President Barack Obama's new policy that would stop the deportation of some illegal immigrants who were brought to the country as children, only saying he would "replace and supersede" it with a long-term overhaul if he is elected president.

The new proposals Romney offered include reallocating the current number of green cards to give priority to legal immigrants who want to unite their families "under one roof". He also said he would exempt from green-card caps the spouses and minor children of legal permanent residents.

As he started speaking, Romney's campaign released an outline of his plan, which would include giving green cards to immigrants who earn advanced degrees at American universities; providing a path to legal status for illegal immigrants who serve in the military; and cutting red tape.

Romney also used the opportunity to attack Obama, saying the president failed to act until he was "facing a tough reelection and trying to secure your vote." He also attacked the new deportation policy as "a temporary measure".

However, new polls found that the new measure, announced last week and could affect about 800,000 people, very popular among Latino voters, who are disappointed by tough talks on immigration by the GOP candidates during their primaries, with Romney one of the toughest.

Romney spoke one day before Obama, who is scheduled to speak to the same convention Friday. The GOP camp is struggling to gain a foothold among Latinos, the largest ethnic minority which made up 9 percent of the 2008 electorate, according to a Pew Hispanic Center analysis of exit polls. Obama won the Hispanic vote 67 to 31 percent over Republican John McCain in 2008.