The search for English Premier League footballer Emiliano Sala, which disappeared over the English Channel earlier this week, has been called off.
Authorities say there is little chance anyone aboard the plane had survived.
Sala, Cardiff City's new signing, and the plane's pilot, David Ibbotson, have been missing since Monday.
Rescuers have scoured 2600 sq km but have found no trace of the aircraft or those on board.
"We reviewed all the information available to us, as well as knowing what emergency equipment was on board, and have taken the difficult decision to end the search," Guernsey Harbour Master Captain David Barker said in a statement.
After the plane disappeared, a recording emerged of a fearful voice message Sala apparently sent in which he expressed concern about the single-engine Piper Malibu aircraft he was flying in.
The 28-year-old Argentina-born forward was en route from Nantes in western France to make his debut for Welsh team Cardiff City.
Cardiff owner Vincent Tan said in a statement on Thursday that everyone at the club would continue to pray for Sala, Ibbotson and their families.
"Monday evening's news shook everyone at Cardiff City FC to the core," he added.
"We were looking forward to providing Emiliano with the next step in his life and career.
"Those who met Emiliano described a good-natured and humble young man who was eager to impress in the Premier League."
Meanwhile, Sala's sister has begged rescue workers to keep looking for his missing plane after the search was formally called off.
An emotional Romina Sala, speaking in Spanish, told reporters in Cardiff that she feels her brother and his pilot are still alive.
Nantes reacted angrily at the decision to formally call off the search for his missing plane and demanded it be resumed via Twitter.
"This cannot stop. The club and its supporters are demanding that the search for EmilianoSala1 continues, for his family. Together, for Emi!"
Barker acknowledged Sala's family were not content with the decision to stop actively searching, but said he was "absolutely confident" no more could have been done.
"The incident remains open and we are continuing with our broadcasts to ships and aircraft that are passing through the area and asking them to report anything that may be linked to the missing aircraft," he said.