LONDON - Two brothers suspected of plotting to make a chemical bomb for an attack in Britain have denied all accusations, their lawyers said, as police continued to search their home.

The men, aged 23 and 20, were held during a dawn raid on Friday when more than 250 police officers, some in chemical protection suits, stormed their house in east London.

The 23-year-old brother was shot in the shoulder during the raid, one of the biggest operations since last July's suicide attacks in London, although police said it was not related.

Specific intelligence had suggested the house might have been used to make a toxic bomb for an attack in Britain, police sources said.

"He says there's absolutely not a word of truth in any of it," the wounded brother's lawyer Kate Roxburgh said. "He says the police are not going to find anything because there is nothing to find."

His brother's lawyer, Julian Young, said earlier his client had also denied he was involved in any terrorism plot, adding: "To date I have seen no evidence showing that he has been."

Both men are being questioned at London's top security Paddington Green police station after the wounded brother was moved there from hospital on Sunday.

Police said they were still concentrating their search on the suspects' house in Forest Gate, an ethnically mixed area with a sizeable Muslim population. They searched the men's work places on Saturday.

Officers are looking for "some form of viable chemical device" that could kill -- a conventional bomb laced with toxic material, a police source said.

Both men's lawyers rejected newspaper reports that the 23-year-old suspect had been shot by his brother in a scuffle with police.

"When he was shot he was standing on the stairs, his brother was a couple of stairs up and behind him," Roxburgh said, describing the report as "absolute nonsense".

British firearms police have been under the spotlight since they shot dead an innocent Brazilian man, Jean Charles de Menezes, in the weeks following last year's suicide attacks. They wrongly identified him as a suicide bomber.

Young said the case struck him as similar to the Menezes shooting.

Asan Rehman, a spokesman for a family arrested from a neighbouring house but then freed, told Reuters the two brothers, were Muslims and of Bangladeshi origin.

Police have said nothing suspicious was found in an initial search of the house and that neighbours are not in danger.