U.S. Capitol Police have removed several suspicious packages from the Hart and Russell Senate Office Buildings.

An email to Senate offices said, “The U.S. Capitol Police have removed the suspicious package from the Hart Senate Office Building and the envelopes from the third floors of the Hart and Russell Senate Office Buildings. The areas are now open.”

Earlier Wednesday, loudspeaker alerts announced the discovery of packages on the first and third floors of Hart, while an email to the Senate community notified offices that police were responding to “a suspicious envelope on the third floor of the Russell Senate Office Building.” The email directed “all staff and other personnel” to “avoid this area until further notice.” Other news organizations reported that the suspicious envelope was found in the office of Alabama Republican Sen. Richard C. Shelby.

CQ Roll Call has confirmed that at least one of the suspicious packages in Hart was also an envelope.

Senate Sergeant-at-Arms Terrance Gainer confirmed that the mailings were hand-delivered, an important distinction coming on the heels of confirmation Tuesday that the Senate Mail Handling Center intercepted a letter that preliminarily tested positive for the deadly poison ricin, addressed to Mississippi GOP Sen. Roger Wicker.

Gainer on Tuesday evening emphasized that the contaminated envelope addressed to Wicker never made it to the Capitol, which he attributed to the effectiveness of the strict mail processing protocols in place as well as the stellar professionalism of the mail handlers.

A little after 1 p.m. on Wednesday, Gainer sent another memo to staff to circulate among D.C. and state offices. Though he did not make mention of the events earlier in the day in Hart and Russell, he alluded to the incidents, instructing staffers not to accept any sealed envelopes delivered directly to them unless delivered by “a uniformed Senate Post Office employee or a government courier bearing a bona-fide government ID.”

He added that “due to the most recent ricin attack, mail delivery will not be available on Thursday, April 18 or Friday, April 19,” but said he expected operations to return to normal next week.

On Wednesday morning, authorities also announced that another letter suspected to contain ricin was intercepted en route to the White House.

The Associated Press reported Wednesday that both letters to Wicker and the White House contained this message: “To see a wrong and not expose it, is to become a silent partner to its continuance.” Both letters were signed, “I am KC and I approve this message,” according to The AP.

Meanwhile, the Saginaw, Michigan, office of Democratic Sen. Carl Levin received a “suspicious-looking letter.”

“The letter was not opened, and the staffer followed the proper protocols for the situation, including alerted the authorities, who are now investigating,” Levin said in a statement. “We do not know yet if the mail presented a threat. I’m grateful for my staff’s quick response and for government personnel at all levels who are responding.”

Sens. John Cornyn, R-Texas, and Jeff Flake, R-Ariz., also reported receiving suspicious envelopes at district offices in their home states.

In a memo to staff Tuesday, Gainer said that in the absence of the involved screening process for mail addressed to Capitol Hill offices, senators’ state headquarters should employ a “postal sentry,” a special device, to open all mail.

Calling it “the only defense available in state offices for this type of threat,” Gainer described the postal sentry as “a lightweight desktop device that provides sufficient airflow and filtration to reduce the release of potentially harmful particles while opening mail in an office setting.”