Nevada state officials have confirmed an envelope sent to a Microsoft office in Reno from Malaysia had anthrax bacteria present.
Malaysian Prime Minister Mr Mahathir Mohamad said today the United States has shared no information over the contaminated letter.
"They don't give us any information. Once we get the information we will investigate," Mr Mahathir told reporters when asked whether police were making progress into links between the postal germ attack and Malaysia.
Mr Mahathir and Foreign Minister Mr Syed Hamid Albar cautioned against jumping to conclusions the anthrax cells were placed in the envelope in Malaysia.
"We are not a country that produces anthrax," the foreign minister told a news conference.
Malaysian police said Washington had so far made no request for help or given details about the letter. It was originally posted from the United States to a Microsoft vendor in Malaysia and was returned with pornographic magazine pages smeared with anthrax cells.