Gardaí say that around 2,000 people attended a protest in Ballinasloe this afternoon to demonstrate against the planned closure of an acute inpatient psychiatric unit in the town.
The Health Service Executive says that the 22 acute beds in St Brigid's Hospital will close by the end of the year and that enhanced community services will replace the unit.
The decision to close the unit followed a review of acute psychiatric services in the Galway-Roscommon area.
The HSE says resources need to be "re-shaped and focused on community based care" to implement the "Vision for Change" plan.
35 acute inpatient beds will be maintained in Galway city and 22 acute inpatient beds will be available in Roscommon.
An additional 15 new specialist beds will be provided in the acute mental health unit in Galway.
These will include beds for eating disorders, psychiatry of later life and mental health intellectual disability.
The HSE says the changes will not result in job losses, as staff will be redeployed.
It says community mental health teams will be developed and strengthened.
The plan is to provide care and treatment nearer to service users' homes.
But opponents of the closure say the infrastructure for community services is not yet in place.
Chairman of the recently-formed East Galway Mental Health Action Group Padraig Mulligan this afternoon described the planned closure as "unacceptable and unreasonable".
That call was echoed by the Bishop of Clonfert, John Kirby, who said the retention of services at St Brigid's was an important issue for the area.
Concerns have also been raised at the cost implications of the proposed closure after €2.9m was spent on refurbishing the unit.