One Direction says they are "completely devastated" after former member Liam Payne was found dead in Buenos Aires on Wednesday.
Payne, 31, had been staying at a hotel in Argentina's capital, and fell from a third-floor balcony.
His death sparked an outpouring of grief from fans of the boy band, which rocketed to fame after forming as part of a British reality television show in 2010 before splitting up six years later.
A joint statement from remaining members Louis Tomlinson, Zayn Malik, Niall Horan and Harry Styles said they would have more to say in time.
"But for now, we will take some time to grieve and process the loss of our brother, who we loved dearly," the statement said.
"The memories we shared with him will be treasured forever.
"For now, our thoughts are with his family, his friends, and the fans who loved him alongside us.
"We will miss him terribly. We love you Liam."
Tomlinson and Malik struggle with 'idea of saying goodbye'
Separately, Tomlinson and Malik put out individual statements.
Tomlinson remembered Payne as "the most vital part of One Direction".
"I first met Liam when he was 16 and I was 18, I was instantly amazed by his voice but more importantly as time went on I got a chance to see the kind brother I'd longed all my life for," he wrote on Instagram.
"Liam was an incredible songwriter with a great sense of melody, we often spoke of getting back in the studio together to try and recreate the writing chemistry we had built up in the band."
He added he would be there for Payne's son Bear as an uncle to "tell him stories of how amazing his dad was".
"I feel beyond lucky to have had you in my life but I'm really struggling with the idea of saying goodbye," he said.
"I'm so grateful that we got even closer since the band, speaking on the phone for hours, reminiscing about all the thousands of amazing memories we had together is a luxury I thought I'd have with you for life.
"I would have loved to share the stage with you again but it wasn't to be."
Malik too mulled over "so many more conversations" he wished he could have with his former bandmate.
"I never got to thank you for supporting me through some of the most difficult times in my life, " he wrote on Instagram.
Malik described Payne as always knowing "which way to steer the ship next".
"I lost a brother when you left us and can't explain to you what I'd give to just give you a hug one last time and say goodbye to you properly and tell you that I loved and respected you dearly."
The band's statements follow a release from Payne's family members who said they were "heartbroken" over the shock death.
"We are heartbroken. Liam will forever live in our hearts and we'll remember him for his kind, funny and brave soul."
"We are supporting each other the best we can as a family and ask for privacy and space at this awful time."
Autopsy shows injuries consistent with fall
In a statement, Argentine police said they had received calls for help to deal with "an aggressive man who could be under the effects of drugs and alcohol" at the CasaSur Hotel.
Authorities have not said whether Payne tumbled over the balcony's barriers accidentally, or if he jumped.
Initial autopsy reports showed internal bleeding and 25 traumatic injuries to his skull, limbs and abdomen, consistent with a fall, according to the Argentinian prosecutor.
It said those injuries alone were enough to cause his death.
There were no signs of a third party being involved, it said, but described Payne's case as "suspicious", saying it was likely the star had been taking alcohol and drugs.
The prosecutor added evidence suggested Payne "was going through some kind of substance abuse episode" at the time.
The police statement said the hotel's manager had heard a loud noise at the back of the building, and when officers arrived they found that a man had fallen over the balcony in his room.
While One Direction had not released new music for almost a decade, the group's former members remained active solo artists.
The English-Irish heart-throbs were thrust together as part of reality TV show The X Factor and went on to release five albums, selling around 70 million copies globally.
Payne, born in Wolverhampton, has been described as "fundamental" to the group's appeal.
He had posted on social media about his time in Buenos Aires ahead of his death, which had included attending the concert that former band mate Horan had given on October 2.