Two members of an Garda Síochana, who were arrested in connection with an investigation into suspected courption in the force, have had their periods of detention further extended tonight.

A Garda Superintendent, and a detective Garda are to be questioned for a further 12 hours. The Superintendant is suspected of disclosing information.

The Detective is being detained on suspicion of perverting the course of justice.

A third Garda, an Inspector, arrested as part of the investigation, was released without charge this evening and a file is to be sent to the Director of Public Prosecutions.

He was questioned for 12 hours today about suspected drugs offences

The Garda Inspector has also been suspended from duty.

The three were arrested this morning by officers from the National Bureau of Criminal Investigation and Special Crime Operations investigating the suspected disclosure of information from a CAB investigation into an organised criminal gang in the midwest.

The Garda Síochána Ombudsman Commission has been informed of the arrests.

This morning's arrests are part of a major Garda investigation into the suspected disclosure of confidential information to a criminal gang in the midwest about a CAB investigation into its activities.

The gang is suspected of being involved in various criminal activity including drug trafficking and its assets have been targeted by the Criminal Assets Bureau.

In its largest operation so far this year, the CAB carried out eight searches in Limerick, Tipperary and Dublin in March.

It seized 115 cars and thousands in euro and sterling from the gang, which it believes to be the proceeds of crime.

However CAB also suspected that information from its investigation had been leaked to members of the criminal gang.

Gardaí began a criminal investigation led by the Assistant Commissioner in charge of Special Operations John O'Driscoll and the National Bureau of Criminal Investigation.

The investigation team is based in Dublin and in a series of co-ordinated searches this morning in the southern half of the country, the three Garda members were arrested.

The superintendent has been arrested on suspicion of disclosing information likely to have a harmful effect, the inspector for a suspected drugs offence and the Garda detective on suspicion of conspiracy to pervert the course of justice.

The detective is one of two gardaí who had previously been arrested as part of this inquiry but on suspicion of committing different offences.

Deputy Commissioner John Twomey said An Garda Síochána is fully committed to investigating any alleged wrong-doing or corruption involving Garda personnel, and will work with other relevant agencies in doing so.

Minister for Justice Charlie Flanagan said: "While I obviously can’t comment on individual cases, I expect a thorough and timely investigation".

Taoiseach Leo Varadkar said he is awaiting a briefing from Minister Flanagan regarding the arrests.

However, he said it was "obviously a serious development".