Two more national institutions became the latest targets Wednesday in a spate of incidents in which envelopes containing a suspicious white powder raised alarm among employees, who feared that the substance could be laced with anthrax. Both the Bank of Israel's Jerusalem office and the Tel Aviv offices of Army Radio received such envelopes on Wednesday. Both envelopes were sent to the Biological Sciences Laboratories in Petah Tikva. Police sources said that they expected to receive conclusive answers as to the chemical makeup of the powder within two days. While not confirming that this week's incidents were related, senior police officers confirmed the seeming similarity and said that they were "aware of the general situation." A Tel Aviv Police District spokesman said that his district was responsible for gathering the evidence related to the multiple incidents, and that, should the need arise, it would take the lead role in any criminal investigation into the sending of the envelopes. Immediately after an administrative worker at Army Radio opened the envelope, which arrived with a computer-printed address label, he noticed the white powder that spilled out. Concerned that the powder could be a dangerous substance, workers contacted the police. Police bomb squads arrived on the scene, evacuated the office, and called in special biohazard teams from the Environment Ministry to take samples of the substance for testing. A similar scene was repeated at the Bank of Israel, where an envelope containing white powder was detected during a preliminary screening process that all mail undergoes. Once again, specialists from the Environment Ministry were called in to take samples and dispose of the envelope. On Wednesday, the Prime Minister's Office in Jerusalem was partially evacuated after a suspicious envelope was found during a routine mail check. Following an X-ray scan of the envelope, a police sapper was called to the scene. Also on Wednesday, envelopes containing white powder were received at the Tel Aviv Stock Exchange. A day earlier, an envelope with a similar substance was discovered mailed to Hebrew University's Mount Scopus campus. Private companies, including Mei Eden in Bnei Brak and Elbit in Haifa, have also received similar envelopes since the beginning of the week.