Four people have died in two separate crashes in counties Donegal and Galway.
Two men and one woman died in a two-car collision in Corravaddy, on the outskirts of Letterkenny at about 1am yesterday.
Gardaí are trying to establish why the two cars crashed head-on.
The victims have been named locally as Stephen McCafferty, 19, Teresa Robinson, who would have turned 21 at the weekend, and Kaylem Ó Murachaidh.
Another man injured in the crash was taken to Letterkenny University Hospital.
Elsewhere, a 26-year-old man died in a single-vehicle crash on the N65 Loughrea to Killimor Road at around 2.45am.
He has been named as Tony Rice, a member of popular Irish band Big Generator.
Mr Rice was seriously injured when his car hit a concrete barrier. He was taken to University College Hospital Galway and was later pronounced dead.
Gardaí appealed for witnesses, in particular anyone who was on that stretch of road between 2.30am and 2.45am, to contact Balinasloe Garda Station on 090-9631890, the Garda Confidential Telephone Line 1800-666-111 or any garda station.
The deaths bring to 12 the number of people killed on Irish roads since Sunday.
106 people have died on Irish roads since January - 19 to date in July alone - and road deaths are up over 18% on last year.
Four people died yesterday in three separate road crashes in counties Meath, Kildare and Donegal.
Mayor of Letterkenny Councillor James Pat McDaid offered his condolences to the families of those killed.
Speaking on RTÉ's Six One News, Cllr McDaid commended the work of the gardaí and the emergency services and appealed to people to take care on Irish roads over the bank holiday weekend.
"It's a very tough time for them [the families]. Families have been torn apart."
He added: "Everyone's in shock and sadness here in Donegal."
The Road Safety Authority has called on the Government to increase the number of gardaí in the traffic corps.
RSA chairperson Liz O'Donnell appealed to Minister for Transport Shane Ross for his support on adequate resourcing of visible policing.
"We do need more visible policing and we discussed this at length with the minister this week. We need his support to get the resources for road policing back up there."
Ms O'Donnell sent her condolences to the families of those involved.
Almost 600 arrested on suspicion of drink-driving this month
Separately, Superintendent Aidan Reid of the Garda National Traffic Bureau has said that 596 people have been arrested on suspicion of drink-driving since the beginning of July.
Speaking on RTÉ's Six One News, he said that drink-driving is a concern and gardaí are targeting high-risk areas.
He said there are currently 708 members of the traffic corps, but the policing of roads is everyone's business.
