The United States will stop deporting young migrants whose parents entered the country illegally who satisfy broad criteria, in a move that will be seen as a concession by President Barack Obama to the Hispanic community ahead of November's election.
The move applies to minors brought to the country before the age of 16, who are currently under 30, are in school or have graduated from high school, and have not been convicted of a felony, officials said.
Obama said on Friday his administration's intitiative was "the right thing to do" but not a permanent fix to the country's perceived problem with undocumented migrants.
"This is not amnesty. This is not immunity. This is not a path to citizenship. It is not a permanent fix," Obama told reporters at the White House.
The move provoked condemnation from conservative Republicans who portrayed it as a bid by the president to solidify his hold on the youth and Hispanic vote that could be critical in several swing states in November.
Lindsey Graham, a Republican senator from South Carolina, derided the policy change as "a classic Barack Obama move of choosing politics over leadership".
"This decision avoids dealing with Congress and the American people instead of fixing a broken immigration system once and for all," he wrote on Twitter.
Jan Brewer, the Republican governor of Arizona, accused Obama of imposing immigration reform by sidestepping Congress.
“It doesn’t take a cynic to recognize this action for what it is: blatant political pandering by a president desperate to shore up his political base," said Brewer.
But Janet Napolitano, the US secretary of Homeland Security, announcing the policy, said the nation's immigration laws should be enforced in a "firm and sensible manner".
"But they are not designed to be blindly enforced without consideration given to the individual circumstances of each case.
Nor are they designed to remove productive young people to countries where they may not have lived or even speak the language. Discretion, which is used in so many other areas, is especially justified here."
The decision will go some way to enshrining the goals of the so-called DREAM Act (Development, Relief, and Education for Alien Minors), legislation backed by the White House that could lead to young migrants, brought to the US by parents who entered the country illegally, gaining permanent residency.
The legislation, opposed by Republican presidential candidate Mitt Romney and conservative Republicans, has failed to pass Congress and become law.
Obama said there was still time for Congress to pass the DREAM Act this year and called for reforms to the US immigration system "that continues to improve our border security, and lives up to our heritage as a nation of laws and a nation of immigrants".
Up to 1.4 million undocumented migrants are estimated to be affected by Obama's policy shift, about 70 per cent of whom are Mexican, according to the Pew Hispanic Center, a nonpartisan research group. About 400,000 people are currently deported from the US each year.
Speaking to Al Jazeera from Washington DC, Brent Wilkes, the executive director of the League of United Latin American Citizens, said the US Latino community was "delighted that Obama has taken this initiative".
"But this is not the DREAM Act, which is something we really hoped to get passed in Congress. The DREAM Act would allow for folks to have permanent legal residency and a pathway to citizenship. This divert action doesn't do that,” Wilkes said.
"It only prevents their deportation and perhaps in some cases gives work permits to these young folks who have been here for a long time, but it doesn't give them a pathway to citizenship and we are going to keep pushing for that."