Crowds and participants attending the America's Cup yachting competition in New Zealand are being warned to take safety precautions after a terror alert.
The event has drawn thousands of fans from around the world
Counter-terrorism police are investigating three threatening letters, including one containing cyanide, which were sent to the US Embassy and the British and Australian High Commissions in the capital, Wellington.
Assistant Police Commissioner for Counter-terrorism, John White, said the identical letters were intercepted and "secured" at the Auckland Mail Centre after staff noticed some white powder.
"A small quantity of cyanide (was) in one of the letters," Mr White said.
"It's quite a serious situation and we wouldn't want to take it lightly," he said.
He said the threats related to "terrorist acts" that could occur during the final races of the America's Cup in Auckland if there was an escalation in the Iraq crisis.
The sailing event has already been hit by weather problems
Government officials say they are concerned the threats may be the action of a disturbed person using a political pretext for their own ends.
Police warned that the cyanide was dangerous, could be fast acting if swallowed and could be absorbed through the skin.
Mr White urged people at the America's Cup village for the event to take precautions and be careful over food and drink.
A fourth letter containing white powder was addressed to the New Zealand Herald newspaper, police said.
A potentially lethal dose of cyanide was sent in a
threatening letter to the US Embassy shortly before the New Zealand Golf Open in January 2002.
Mr White said police could not yet rule out the possibility that the latest letters came from the same person.
This is the action of a disturbed person but using a political pretext for the action she or he has taken
New Zealand Foreign Minister
Foreign Minister Phil Goff confirmed he had been briefed on the alerts.
"This is the action of a disturbed person but using a political pretext for the action she or he has taken," he said.
"The worrying thing is that at least one of the letters seemed to have traces of cyanide rather than being the standard hoax letter."
Meanwhile, race four of the America's Cup was cancelled for a fifth time on Tuesday due to forecasts of high winds and choppy seas.
Swiss challengers Alinghi hold a 3-0 lead and need to win just two of the six remaining races to take the title from Team New Zealand.