Protesters have set up camp outside a factory which makes components for fighter jets.
The members of anti-war and anti-arms trade groups are hoping to disrupt work at the EDO MBM Technology factory in Moulsecoomb, Brighton.
Previous action, reported by The Argus in May, closed the factory down for two days, costing the company more than £17,000.
This time the protest camp, outside the factory on the Home Farm industrial estate off Lewes Road, includes children as young as six months.
Joyoti Greck, who is at the camp with Ombaashi, three, and Shanti, eight months, said: "We don't want a factory on our doorstep producing weapons used to take the lives of children in other parts of the world."
Robin Horsell, 44, from London, said: "There are people living without basic needs.
"This factory could be making things to save lives instead of taking them."
The camp, which began on Sunday and will continue until Thursday, will include daily protests outside the factory when the workers arrive and leave.
Organiser Chris Osmond, 24, said: "We want to encourage as many people as possible to come and make noise here.
"We can make a difference - intense campaigning and direct action stopped Bayer from producing GM foods here."
Activists have also written to all EDO MBM workers.
No one at the factory was available for comment.
The company has previously said it respects the campaigners' right to protest but sells its products in strict compliance with UK export regulations and policy.
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