A coalition of US military veterans of the wars in Iraq and Afghanistan is suing the US government.
The class-action lawsuit on behalf of hundreds of thousands of veterans claims they have been denied disability pay and mental health treatment.
The legal case against the US Department of Veterans Affairs (DVA) seeks widespread changes in the agency.
It says the DVA has deliberately cheated some traumatised war veterans out of benefits owed to them.
The case was filed on Monday in a federal court in San Francisco.
Cost 'incalculable'
Suing on behalf of hundreds of thousands of veterans, the coalition claims they have been let down on several fronts.
These include the provision of prompt disability benefits, additional staff to reduce waiting times for medical care and services to treat post-traumatic stress disorder.
The coalition says the DVA worked with the Pentagon to mis-classify post-traumatic stress disorder claims as pre-existing personality disorders.
The cost to veterans, their families and the nation will be incalculable, it says, unless systematic and drastic measures are instituted immediately.
There has been no reaction to the legal action from the Department of Veterans Affairs.
Several Congressional committees and a presidential commission are now studying ways to improve health care for war veterans.
