A British government minister urged the public to be "alert but not alarmed" Wednesday, a day after police said they arrested six men and found traces of the deadly poison ricin in a London apartment.
"It's understandable that people are concerned," Home Office minister Beverley Hughes told the British Broadcasting Corp. "But we need to keep it in perspective. People need to be alert, but not alarmed and panicked."
The six men arrested on Sunday in north and east London were being questioned Wednesday, London's Metropolitan Police said.
Anti-terrorist police said Tuesday they had found "material and items of equipment" in an apartment in north London's Wood Green district, and that a "small amount of the material" tested positive for ricin. One of the men, who are all of North African origin, was arrested in the apartment, police said.
Doctors around Britain were warned to look for symptoms of exposure to ricin, one of the most powerful poisons and one for which there is no antidote. Symptoms include fever, stomach ache, diarrhea and vomiting.
"This makes us feel really scared. We are only three or four meters (yards) away from it," said Ismail Ucur, 19, who lives opposite the apartment where the poison was found.
"We should have been told what was going on. We saw the police and then people in protective gear and we asked them what was happening but they didn't tell us," Ucur said.
"It's terrifying to think it was on our doorstep," added Ali Goren, 20, who works at a cafe next to the apartment.
The Daily Mirror newspaper showed a skull and crossbones against a map of Britain on its Wednesday front page under the headline "It's here." The Sun, Britain's biggest circulation daily, said the discovery revealed a "factory of death."
The public health director for London, Sue Atkinson, urged people not to be alarmed. "What has been found is a very small amount of this and it's quite difficult to perhaps use it for mass destruction," she told the BBC.
But Prime Minister Tony Blair said Tuesday that the find highlighted the threat posed by weapons of mass destruction.
"As the arrests... show, this danger is present and real, and with us now, and its potential is huge," he said.
Ricin (pronounced RICE-in) is derived from the castor bean plant, which is grown around the world, and is relatively easy to produce. It has been linked in the past to Usama bin Laden's Al Qaeda terror network and Saddam Hussein's regime in Iraq.
In Washington, U.S. officials said Tuesday that no Al Qaeda links had yet been established to the London arrests, but that it was a matter being investigated.
Police in Britain have not publicly identified the six men and have refused to specify what country or countries they were from, saying only that they were in their late teens, 20s and 30s. They were not immediately charged with a crime.
Metropolitan Police refused to confirm media reports that some of the men are Algerian. Police on Wednesday refused to confirm reports that they had discovered a makeshift laboratory in the Wood Green apartment, or that they were looking for more ricin elsewhere.
U.S. officials said in August that the Islamic extremist group Ansar al-Islam had tested ricin along with other chemical and biological agents in northern Iraq, territory controlled by Kurds, not Saddam. The group is allegedly linked to Al Qaeda.
United Nations weapons inspectors who left Iraq in 1998 listed ricin among the poisons they believed Saddam produced. U.S. troops also found traces of the substance at suspected Al Qaeda biological weapons sites in Afghanistan.