President Trump Donald John TrumpBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Pelosi: Trump Supreme Court pick 'threatens' Affordable Care Act MORE's supporters chanted “lock her up” ahead of his arrival at a rally in Mosinee, Wis., on Wednesday evening, just hours after the Secret Service said it found "potential explosive devices" in mail sent to former Secretary of State Hillary Clinton Hillary Diane Rodham ClintonThe Memo: Trump furor stokes fears of unrest Bloomberg rolls out M ad buy to boost Biden in Florida Hillicon Valley: Productivity, fatigue, cybersecurity emerge as top concerns amid pandemic | Facebook critics launch alternative oversight board | Google to temporarily bar election ads after polls close MORE at her home in Chappaqua, New York.

Video of the rally showed the crowd chanting the phrase as Sen. Leah Vukmir (R) delivered remarks shortly before Trump’s scheduled appearance.

Tonight: Trump crowd chants "lock her up" after bomb mailed to Hillary Clinton pic.twitter.com/X4ZiqONhH3 — TheBeat w/Ari Melber (@TheBeatWithAri) October 24, 2018

The chant, which has become a regular feature of Trump's rallies since his presidential campaign, came hours after authorities discovered potential explosive devices had been sent to Clinton’s New York residence, in addition to other Democrats including former President Obama, Rep. Maxine Waters Maxine Moore WatersPowell, Mnuchin stress limits of current emergency lending programs Pelosi: House will stay in session until agreement is reached on coronavirus relief Omar invokes father's death from coronavirus in reaction to Woodward book MORE (Calif.) and former Attorney General Eric Holder Eric Himpton HolderThe Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements Obama endorses Warnock in crowded Georgia Senate race The Hill's Campaign Report: Trump's rally risk | Biden ramps up legal team | Biden hits Trump over climate policy MORE.

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Each of those targeted by the suspicious packages have been criticized repeatedly by Trump, who condemned the attempted attacks as “abhorrent” during remarks from the White House East Room on Wednesday afternoon.

“We are extremely angry, upset, unhappy about what we witnessed this morning and we will get to the bottom of it,” he said.

White House press secretary Sarah Huckabee Sanders also said the president and administration officials are monitoring the developments.

"Our condemnation of these [despicable] acts certainly includes threats made to CNN as well as current or former public servants. These cowardly acts are unacceptable and wont be tolerated," she tweeted.

Clinton and other bipartisan lawmakers called for officials to dial back their rhetoric in response to the attempted attacks.

Trump was stumping for Wisconsin Gov. Scott Walker (R) in his reelection bid against state schools superintendent Tony Evers (D), and Leah Vukmir, who is challenging Wisconsin Sen. Tammy Baldwin Tammy Suzanne BaldwinSenators introduce bipartisan bill to mandate digital apps disclose country of origin Keep teachers in the classroom Cher raised million for Biden campaign at LGBTQ-themed fundraiser MORE (D).

Walker is battling Evers in a tight race, which RealClearPolitics has dubbed a "toss-up." A RealClearPolitics average of polling gives Evers a 3.6 percentage point edge in the race.

Baldwin has a double-digit lead over Vukmir, according to a recent Marquette Law School survey of likely voters.

--Updated on Oct. 25 at 7:33 a.m.