The Quinn Group has called on local people to condemn a firebomb attack on its premises.
Oil was poured into a manhole carrying cables in last week's attack on part of the Quinn Group's communication network in Co Fermanagh. The fuel was then set alight.
In separate incidents, three high voltage electricity poles supplying the plants were cut down and another pole was set alight.
The March 27 attack is the latest in a series on Quinn Group plants, since new management took over the firm in 2011.
The plants were built up along the Fermanagh/Cavan border by bankrupt billionaire Sean Quinn – who has strong local support.
A fire at group headquarters in January last year followed an incident the previous December, when a lorry was driven into the same complex.
Mr Quinn condemned the attacks at the time.
Yesterday, the Quinn Group hit out at the "renewal of mindless sabotage attacks" on the company's property. "Silence is not enough; there cannot be any room for equivocation," the firm said.