Security fears continued Friday in Malaysia's capital after police and diplomats confirmed the Spanish embassy became the thirteenth mission to receive a suspicious package in the mail.

The alarm was raised after officials placed it through security checks and the sender could not be contacted, a Spanish embassy source said.

"We determined this envelope was suspicious and we tried to get back to the sender and this was impossible," the source told AFP.

"The police came immediately and were diligent and very effective and removed the envelope."

Embassy officials and police did not open the package, which arrived before noon Friday, but like those received by 12 other diplomatic missions this week it was sent by express mail through the national post, said police.

Sent for testing

The previous packages have contained compact discs and threatening notes relating the action to the treatment of Muslims, and most have contained liquid or powdery substances that have been sent for testing.

The government has tried to calm the diplomatic community by vowing to investigate thoroughly and saying the packages are only preying on fears after the weekend bombings on the Indonesian island of Bali.

"They do have a psychological impact. You do scare people," said regional security analyst Zakaria Ahmad from the Help University College.

Authorities "say that everything is under control but then you get this kind of thing happening, so this puts the credibility of the government under question," he said.

Kuala Lumpur's criminal investigations chief Abdul Aziz Bulat said the package was postmarked from nothern Kelatan state, where many of them originated.

Return addresses

He said police believed the senders had chosen return addresses at random, adding that a check of an address on one of the parcels had led to a dumbfounded warehousing and packaging company.

"When we called they did not know anything about the package," he said.

The packages started arriving on Tuesday afternoon, with Japan, Germany, Thailand, Canada, the Philippines, and Singapore receiving deliveries.

The United States, Russia, Britain, France and Australia received packages on Wednesday morning, and the European Commission got one on Thursday.