WASHINGTON - ENVELOPES with white powder were received recently at more than 40 US governors' offices and 16 US embassies in Europe, but nothing dangerous has been found in them so far, officials said on Wednesday.

The State Department said the envelopes were mailed to embassies in Berlin, Berne, Brussels, Bucharest, Copenhagen, Dublin, Luxembourg, Madrid, Oslo, Paris, Reykjavik, Riga, Rome, Stockholm, Tallinn and The Hague.

'Tests conducted to date have all met with negative results. However, we have not received results from all affected embassies,' the department's deputy spokesman Robert Wood said in a statement.

Earlier he said results had not come in yet from the embassy at The Hague.

'All US diplomatic facilities worldwide receive extensive training in responding to these types of incidents. The impact on the day-to-day operations has been minimal,' Mr Wood said.

'The US embassy's consulate building in Bucharest was temporarily closed to the public and reopened Tuesday afternoon. The US embassy's consulate building in Rome remains closed today (Wednesday),' he added.

Spanish security services cordoned off the US embassy in central Madrid on Wednesday after one of the suspicious envelopes sparked what turned out to be a false security alert, Spanish police said.

The FBI said in a statement meanwhile that the offices of more than 40 governors across the country received similar envelopes with a suspicious white powder but the contents tested negative.

The Dallas office of the Federal Bureau of Investigation said the letters were all similar, post-marked from Texas, with the earliest sent on December 8.

The FBI said on December 10 that Alaska Governor Sarah Palin, the former Republican vice presidential candidate, and seven other US governors had received letters with a suspicious white powder.

It said the letters were also sent to governors' offices in Rhode Island, Michigan, Mississippi, Alabama, Minnesota, Montana, and Missouri.

'Sending a hoax letter is serious and can have severe consequences. This is a great drain on each city's response teams,' according to the FBI statement on Wednesday.

In 2001 letters containing anthrax killed five people and spread panic.

Since then, police and fire officers have been called out to investigate suspicious mailings across the country - most of them harmless. -- AFP