Police in protective black boiler suits on Saturday searched an east London house raided the previous day by anti-terrorist officers who arrested two men, shooting and wounding one of them. Police, who said Friday's raid was the response to a specific threat of attack, refused to comment on news reports that the men were plotting to use a chemical weapon. Most of the front of the house has been covered in scaffolding shrouded with white plastic sheeting, shielding it from the view of passers-by. At least a dozen police officers manned cordons around the property on Saturday. On Friday, about 300 police, some armed and some wearing protective chemical, biological and radiological suits and acting with the advice of biochemical experts - mounted one of the largest raids in the capital since the deadly bombings of London's transport network in July. Police said they do not believe the suspected new threat was linked to those attacks. Peter Clarke, head of the anti-terrorist branch of London's Metropolitan police, said Friday's raid had been in response to information about a threat from firearms or "hazardous substances." A police spokeswoman said she could not confirm whether the men were suspected of planning to build a chemical weapon or use one already assembled in an attack. Police said officers have not discovered any weapon or device at the site. The wounded man, 23, was shot in the shoulder and taken to a nearby hospital with injuries that were not life threatening. He was later arrested at the Royal London Hospital, where he is under guard. Another man, aged 20, was also arrested at the house and is being held on suspicion of terrorism and questioned at the high-security Paddington Green police station in north London. Neighbors said the arrested men were British-born Muslims and were brothers - but police refused to confirm details about the suspects. "Because of the very specific nature of the intelligence, we planned an operation that was designed to mitigate any threat to the public either from firearms or from hazardous substances," said Clarke. He said the raid followed work by police and MI5 - Britain's domestic spy agency - that "demanded an intensive investigation and response." Clarke said forensic examinations were under way at the house and could continue for several days. Deborah Glass of the Independent Police Complaints Commission said an inquiry into the shooting has begun. It is standard procedure in Britain. She declined to say whether the shooting victim had been armed. Neighbors said a man, a woman and their four teenage children lived in the raided house. They said the wounded man had worked for the postal service. Clarke said an air exclusion zone was set up around the house, but locals were not evacuated from their homes. Shopkeeper Salim Mala, 42, said residents were a mixture of Bengalis, Pakistanis, Eastern Europeans and Britons. In northern England, Greater Manchester Police chief constable Michael Todd said Friday that separate raids last week focused on a gang alleged to be facilitating terrorist activity in Iraq. Those raids disrupted a "known terrorist group," Todd said. Six of eight men arrested are in custody pending deportation on grounds that they are a threat to national security and two others have been released without charge, Todd said.