The Department of Homeland Security (DHS) on Monday said it is expanding its urban area nuclear security program to two new cities, Houston and Chicago, bringing to five the number of regions in the United States where the department and local authorities are stepping up efforts to improve the nation’s capabilities to detect and protect against radiological and nuclear threats.

DHS says that the initial award to Houston provides $3.5 million to begin the region’s planning and planning and analysis this year under the Securing the Cities program, which first launched in the New York City region in 2006 and more recently expanded to Los Angeles/Long Beach in 2012 and the Washington, D.C. area in 2014.

Since 2007 the New York City region has purchased 13,800 radiological detectors and trained more than 19,000 personnel.

As part of Securing the Cities, each region will receive up to $30 million over five years. Once funding is complete, the department’s Domestic Nuclear Detection Office (DNDO) will continue to provide support in the areas of training, exercises, and technical help to ensure each region maintains its detection capability.

DHS says it will begin work in Chicago in subsequent years—likely 2016—as funding becomes available.

Additional regions will be added to the program in the coming years.

“The Securing the Cities program is a key part of the department’s efforts to protect the nation against the malicious use of nuclear and other radioactive materials,” says Homeland Security Secretary Jeh Johnson. “Expanding this program to Houston and Chicago will bring these important capabilities to two more of our country’s largest metropolitan areas.”

Securing the Cities is managed by DNDO. The agency will help law enforcement and first response organizations, including providing various radiological detection equipment, training services, and exercises.

Shortly after DHS announced that Houston and Chicago are being added to the program, a House subcommittee approved the Securing the Cities Act of 2015 (H.R. 3493) codifies the radiological and nuclear threat detection and prevention program within DNDO.