The proposed design for a California driver’s license for immigrants in the country illegally doesn’t meet national security standards, the Department of Homeland Security said.

In a letter, Homeland Security officials told California’s Department of Motor Vehicles that the license would need to state on its face that it cannot be used as federal identification and should contain a unique design or color.

Otherwise, it would not meet requirements under the REAL ID Act, a federal law passed to create national identification standards after the 9/11 terrorist attacks, David Heyman, assistant secretary for policy, and Philip McNamara, assistant secretary for intergovernmental affairs, wrote in the letter obtained by The Associated Press.

While the federal government wants the new license to contain a marker easily recognizable by agents checking for identification at federal buildings or airports for security reasons, immigrant advocates in California have pushed for the licenses to be as similar as possible to those carried by others to avoid inviting discrimination.

Armando Botello, a DMV spokesman, declined to say whether the state would change how the new license would look. He said the state will still aim to issue the document by January 2015.

“While we are disappointed by this ruling, the DMV will continue to work vigorously with lawmakers, affected communities and federal officials to design a license that complies with federal law,” Botello said in a statement Tuesday.

California is one of nearly a dozen states that have enacted laws to issue licenses for immigrants in the country illegally. California passed its law last year and has been striving to make the new license an example for other states to follow.

In California, the proposed licenses would largely look the same as the state’s other licenses but contain different lettering on the front and a notice that the card can’t be used as federal identification on the back.

DMV Director Jean Shiomoto wrote Homeland Security last month seeking approval of the design, saying the agency believed it would meet federal standards.

Like many other states, California has been working to comply with the REAL ID Act. Some states have already complied; others have been deemed noncompliant. Federal officials plan to start enforcing the law in phases, restricting acceptance of identification cards from states that fail to meet the standards for entry to federal facilities and eventually, to board an airplane.

Tanya Broder, a senior attorney at the National Immigration Law Center, said the licenses issued by other states for immigrant drivers have more distinctive markers than California’s proposed design. She said the state can decide not to comply with the federal law and see if authorities will change their mind, or make tweaks to satisfy them.

Some immigrant advocates are resisting the idea of redesigning the license. Jorge-Mario Cabrera, a spokesman for the Coalition for Humane Immigrant Rights of Los Angeles, said advocates already rejected a proposal to create a more distinct license during last year’s debate on the law.

“Right now, we’re not willing to accept any changes,” he said.