Letter to U.S. Consulate tests positive for anthrax

Concern is growing in Pakistan that the anthrax attacks in the U.S. may be spreading to the country

ISLAMABAD, Pakistan (CNN) -- A suspicious letter sent to the U.S. Consulate in the Pakistani city of Lahore has tested positive in initial tests for anthrax and is being sent to the United States for further examination.

Confirming the results, a spokesman for the U.S. Embassy in Islamabad told CNN there had been "several false positives" from tests conducted at Pakistani labs on other letters.

He added that a letter sent earlier to the Islamabad Embassy containing white powder had tested negative for anthrax spores.

The Lahore letter was addressed to the U.S. Consul, but had no return address.

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The local postmark on the envelope was smudged, making it difficult to read.

The mailroom clerk who opened it was wearing a mask and gloves, and is not believed to have been exposed to the suspected spores.

On Sunday, the executive director of Pakistan's National Institute for Health, Dr. Athar Saeed Dil, said there had been no confirmed incidents of anthrax in Pakistan, including environmental samples and testing of individuals.

Suspicious powder

However, he added that testing was not yet complete.

Dil said suspicious powder from a letter received by Pakistan's largest newspaper in Karachi, the Daily Jang, October 23 had not been received yet at the institute.

After being shown a copy of the test results done by a laboratory at Aga Khan Hospital, Dil said it was a preliminary test that could indicate anthrax spores, but noted further testing is required.

Dil also said that a second letter had the same preliminary results that could indicate the presence of anthrax spores.

He did not disclose where the letter was received but said the National Institute for Health would be conducting its own tests for final results.

-- CNN's Allison Flexner contributed to this report