The Obama administration says it will review the cases of more than 300,000 illegal immigrants facing deportation to determine if they can stay in the United States.

In a letter to a group of lawmakers, Homeland Security Secretary Janet Napolitano says officials will review each case to identify “low priority” offenders, including those who have been in the U.S. for a lengthy period, to allow the agency to focus more on deporting convicted criminals and others who pose a threat to public safety.

The new policy was welcomed by Democratic Senator Dick Durbin, who has sponsored legislation that would provide an eventual path to U.S. citizenship for illegal immigrants who arrived in the country as children.

But Republican lawmakers say the administration is circumventing Congress, and that the policy amounts to granting blanket forgiveness, or amnesty, for illegal immigrants.

President Barack Obama's administration has come under fire from immigration advocates for deporting millions of illegal immigrants since taking office in 2009, and for not pushing Congress to pass a comprehensive immigration reform plan.