There has been an arson attack on a Sinn Fein office in Limavady.
The fire at premises on Main Street in the town was reported to police at about 2230 BST on Wednesday.
Local Sinn Fein councillor Paddy Butcher has appealed for calm and urged people not to overreact.
"As regards to Sinn Fein, it's business as usual. This is the marching season, it's a very sensitive time of the year and we have to show leadership - be calm and responsible," he said.
Police have appealed for anyone with information to contact them.
In a separate incident three men in their 20s have been charged in connection with an attack on an Orange Hall in the town.
The charges relate to damage caused to the hall in Catherine Street in the early hours of Thursday morning.
They will appear at Limavady Magistrates Court on 4 August.
SDLP MLA John Dallat described those involved in both attacks as "dangerous elements who should hang their heads in shame".
"Arsonists have no part in building understanding and peace between two communities," he added.