Thousands of federal grants supporting mental health and addiction treatment programs were suddenly terminated late Tuesday, sources told CBS News. 

The abrupt cancellations at the U.S. Substance Abuse and Mental Health Services Administration impacted 2,706 of the agency's discretionary grants valued at around $1.9 billion, a source familiar with the matter told CBS News. 

President Trump's political appointees moved to terminate the funding, not career officials working for SAMHSA, according to the source.

CBS News obtained a termination notice sent by a top SAMHSA official to one grant recipient which outlined said the agency was "terminating some of its awards, in order to better prioritize agency resources" toward priorities "that address the rising rates of mental illness and substance abuse conditions, overdose, and suicide".

"This was not SAMSHA's idea," the source said, noting that many of the canceled grants addressed those priorities. "This was money going to people on the ground who are providing mental health treatment, substance use treatment, recovery support, and prevention resources, which this administration says is a priority."

CBS News has reached out to the Department of Health and Human Services for more information and comment.

SAMHSA, which is a branch of the Department of Health and Human Services, is at the forefront of efforts to improve mental health and address substance abuse across the country. At the national level, the agency leads public health initiatives geared toward reducing the burden of substance abuse and mental illness on communities, while also distributing funds to states and local entities for mental health and addiction services, according to its website. 

A source said that among the newly canceled grants is one that provided $15 million per year to the Opioid Response Network, a program that offers evidence-based education and training to local authorities managing various types of substance use intervention, including prevention, treatment and recovery services. Another $6 million grant to a program called Building Communities of Recovery, which funds community-based resources to increase the availability and quality of long-term recovery support for people with substance use disorder, was canceled, too.

CBS News reached out to the Opioid Response Network and a representative for the Building Communities of Recovery program at SAMHSA.

This latest funding loss comes after the Trump administration's sweeping Medicaid cuts, which impacted a broad array of public health services including some focused on mental health and addiction. Those cuts are set to take effect in full later this year.