Update: Ariana Grande has responded to the tragedy at Manchester Arena on Twitter.
Original story follows.
Reports have since confirmed that Grande was not injured.
The heartbreaking event has shaken the world. Among the concerned are a number of celebrities, including Grande’s friends, Lorde, Kendall Jenner, Taylor Swift, Khloe Kardashian, Nicki Minaj, and Hailee Steinfeld.
"Every musician feels sick and responsible tonight — shows should be safe for you," Lorde tweeted. "Truly a worst nightmare. Sending love to Manchester and Ari."
"What happened in Manchester tonight is absolutely horrible," Jenner wrote. "Sending my love and prayers to those affected."
"My thoughts, prayers and tears for all those affected by the Manchester tragedy tonight," Swift wrote. "I'm sending all my love."
"God bless everyone who was at Ariana's concert," Kardashian tweeted. "My prayers are with you all and poor sweet Ariana. This is heartbreaking."
"My heart hurts for my sister, Ariana & every family affected by this tragic event in the U.K.," Minaj tweeted. "Innocent lives lost. I'm so sorry to hear this."
"I'm at a loss for words," Steinfeld wrote. "My heart goes out to all those affected by this senseless tragedy in Manchester."
“We can confirm there was an incident as people were leaving the Ariana Grande concert last night,” police tweeted. “The incident took place outside the venue in a public space. Our thoughts and prayers go out to the victims."