President Obama

Tragedy struck President Barack Obama's campaign on Friday as a young staffer, 29-year-old Alex Okrent, collapsed in the Chicago headquarters and died, according to campaign officials.

According to The Ticket, Obama, campaigning in Virginia, telephoned Okrent's family to express his condolences and later spoke with other campaign aides by conference call. The aide had been with Obama since 2004 and was working in the "paid media" department of the re-election effort, which handles advertising, a campaign aide said.

Mitt Romney quickly expressed sorrow over Okrent's passing. "Ann & I were deeply saddened to learn of the death of Alex Okrent," he said on Twitter.

"Prayers are with Alex's loved ones and the entire Obama campaign team," Romney's tweet continued.

Top Obama campaign strategist David Axelrod responded: "@MittRomney Thank you, governor. Alex was a beloved member of our team. It's been a very emotional day."

The Chicago Sun-Times reported that Chicago paramedics were called at 10:36 a.m., after Okrent collapsed. He was given emergency treatment at the Obama campaign headquarters in Chicago's Prudential Building. He was taken to North-western Memorial Hospital, where he was pronounced dead. Okrent was a graduate of Wesleyan University in Connecticut, the paper said. ".@HeyAok - we will miss you, Alex. you left a beautiful legacy," the Obama campaign's national field director, Jeremy Bird, said on Twitter, using the late staffer's handle. "We will never forget your spirit or your passion. rest in peace, brother."

Republican National Committee Chairman Reince Priebus joined in the chorus of mourning, saying on Twitter: "So sorry to hear about Obama staffer Alex Okrent. Horrible to lose someone that young. Prayers with his family & Obama staff."