Gardai believe dissident republicans may have been involved in a violent attack at a house in Co Roscommon early yesterday.
More than 20 men armed with baseball bats targeted security guards hired to protect the property in Falsk, near Strokestown.
The house was at the centre of a "heavy-handed" eviction last week.
Eight security workers were injured in the attack. Three of them were taken to hospital with serious injuries.
A badly injured guard dog had to be put down by vets.
Four vehicles were also torched during the incident.
Roscommon Independent TD Michael Fitzmaurice condemned yesterday's violence, but criticised the "ugly eviction" of a local farmer from the property last Tuesday.
An incident room has been established as part of the investigation and gardai are appealing for anyone with information about yesterday's incident to contact them.
A senior source said the dawn raid is being treated "very seriously" and efforts are continuing to identify those involved.
No arrests have yet been made.
Gardai are investigating whether people with dissident links were involved in what has been described as a "well-planned and organised" attack.
The house was at the centre of an eviction last Tuesday, during which a farmer was removed from the property.
Local gardai were present "to preserve the peace".
A garda spokeswoman confirmed that two minor assaults reported during the eviction are under investigation.
The farmer at the centre of the eviction is not suspected of any involvement in yesterday's violence.
It is understood he has financial difficulties that stretch back nearly a decade.
These include a settlement of more than €400,000 which was secured against him by the Revenue Commissioners in 2015 for the under-declaration of VAT.
Land Registry records for the property also show that more than €18,000 was secured in a judgment in December 2008.
This was subsequently registered against his property.
The judgment was obtained by a local company which operated a quarry at the time.
In 2015, the Revenue Commissioners secured a settlement totalling €429,501 against the farmer as a tax defaulter for the under-declaration of VAT.
It included €177,000 in tax owed, nearly €75,000 in interest and more than €177,000 in penalties.
Last January, a judgment mortgage was secured against the farmer in the Midland Circuit Court by Cabot Asset Purchases (Ireland). That judgment was registered against his property last February.
In 2004, the farmer secured a mortgage from IIB Homeloans, the Belgian-owned lender that rebranded as KBC in 2009.
It emerged last year that KBC Bank Ireland sold a chunk of loans to credit- servicing and debt-collection firm Cabot Financial Ireland, a unit of the US-based Cabot group.
Cabot manages about €2.3bn of loans on behalf of clients in Ireland.
TD Mr Fitzmaurice told the Herald that "violence won't solve anything", but banks must find alternative means to handle arrears.
"While I don't condone any type of violence, I believe the very ugly eviction of this family in Strokestown sparked a great deal of anger from local residents," he said.
"People in rural Ireland have had enough of evictions and vulture funds and won't stand idly by and watch families being kicked out of their homes.
"If you look at the history of Ireland, the issue around land and property runs very deep in rural areas, which is something not everyone understands.
"People are just frustrated and are at their wits' end.
"I warned a year ago that mass evictions will lead to incidents of this type.
"I fear that this is only the beginning."