A masked gang armed with crowbars have broken into a house in Garvagh, stealing six guns and tying a woman up in a bathroom.
The three men carried out the attack at Craigmore Road in the early hours of Saturday morning.
After getting into the house they tied up a woman in her 20s.
She was locked in a bathroom while the gang stole six legally-held firearms and drove away from the scene.
Police in Co Londonderry said the woman was left badly shocked by her ordeal.
They have appealed for anyone who witnessed the incident, which unfolded at about 6am, or who has any further information to come forward.