Suspicious packages filled with white powder were sent to the Alaska offices of the state's three-member congressional delegation on Monday, authorities said.

The packages were received in the Fairbanks offices of Sens.Mark Begich and Lisa Murkowski and the Anchorage office of Rep. Don Young. Begich is a Democrat, and Murkowski and Young are Republicans.

The federal building in Fairbanks was emptied soon after the package was discovered and two fire trucks and a hazardous materials unit were deployed outside the building, said Assistant Fire Chief Ernie Misewicz told the Fairbanks Daily News Miner.

Peterson Towers in Anchorage was also evacuated and tightly monitored, while hazardous materials workers from the Anchorage Fire Department examined the site, said Anchorage Police Department spokesman Lt. Dave Parker.

One of the aides at Begich's office opened the express mail package, which had an Arizona return address on it, and saw white powder spill out, said Begich's press secretary, Julie Hasquet.

Similarly a staffer from Young's office discovered a white substance when he opened the package delivered to the Anchorage office, Young's office said in a statement.

No one at Murkowski's Fairbanks office touched the package that was delivered there, Murkowski's spokesman Mike Anderson said in a statement.

The packages, however, were deemed harmless on Tuesday evening.

"The FBI has notified Congressman Young's State Director, Chad Padgett, that the substance is in fact a mixture of concrete and is not hazardous," Young's office said.

The staff member from Begich's office, who opened the package, was examined at a local hospital and released on Monday evening with no apparent ill effects, Hasquet said.

The FBI is leading the inquiry into the incidents, Parker said.

The office opened on Tuesday as usual with staff at work.

Discovery of the packages led to the temporary closure of the entire Fairbanks federal building, where the senators have their Fairbanks offices. The floor containing Young's Anchorage office was also evacuated and closed for a few hours.

Congressional offices have been on alert for packages containing powdery substances since the anthrax attacks of the fall of 2001.

 Young and Begich were not in their offices when the packages were discovered.