Police in the North are investigating the circumstances of a small explosion at a police base in Derry.
At 10.20 last night an explosion was heard at Rosemount police base in the city, a PSNI spokesman said. After the scene was examined a "small improvised device" was found to have exploded.
It is believed the device was thrown into the base. No damage was caused.
Police are appealing to anybody who saw suspicious activity near the base after 10 p.m. to come forward.