Hong Kong police said they defused two large homemade bombs packed with nails and designed “to kill and to maim people" in the latest reported seizure of weaponry during six months of anti-government protests that have shaken the city.

Police said the bombs found Monday evening inside a school on Hong Kong Island were “complete, fully functional and ready to be used.”

The origin of the bombs was not clear.

Police said they were radio-controlled, to be triggered with mobile phones. They contained 10 kilograms (22 pounds) of high explosives and shrapnel that would inflict injury. Their blast could have been felt over a distance of 100 meters (yards) or more.

Alick McWhirter, the police explosive squad’s senior disposal officer, said that had the bombs exploded, they could “have killed and injured large numbers of people.”

In July, police announced the seizure of about 2 kilograms (4.4 pounds) of TATP, which has been used in militant attacks worldwide. Other recent seizures in Hong Kong involved far smaller amounts, just 1 gram, of TATP, or tri-acetone tri-peroxide.