The RUC are questioning two men in connection with a pipe bomb attack in Larne, Co Antrim.
A senior nationalist has warned of a developing loyalist campaign of sectarian violence against Catholics in Northern Ireland.
The SDLP's Mr Denis Haughey met RUC chiefs in Larne just hours after a bomb exploded outside a colleague's house and said he feared the violence could soon claim lives.
He said: "No one has, as yet, been killed in recent times but if it were to go on the threat to life would escalate."
Two arrests were made after the early morning pipe bomb attack against newly elected Larne SDLP councillor Martin Wilson which damaged a door but caused no injuries.
A second device was defused near the home of Mr Wilson's brother, who is on holiday with his family in Canada.
The blast followed the discovery of a bomb attached to a Gaelic football goal post in Downpatrick, Co Down, and warnings that Sinn Fein election posters had been booby-trapped by loyalists in mid-Ulster.
Mr Haughey, a junior minister in the Northern Ireland Executive, said: "In general, I think the sectarian animosities have sharpened in recent time.
"I would imagine that the events which would unfold around Drumcree will possibly raise the temperature again and I am worried about the dangers of escalating intercommunal strife."
It is feared loyalist paramilitaries are intent on causing maximum disruption in Northern Ireland around the disputed Orange Order Parade at Drumcree, near Portadown, Co Armagh, next month.
PA