(CNN) The search for a missing airplane carrying Argentine soccer player Emiliano Sala was called off Thursday with police conceding that "the chances of survival at this stage are extremely remote."
Rescue workers had been attempting to locate the plane since it disappeared from radar near the Channel Islands just before 8:30 p.m. local time (3:30 p.m. ET) Monday. The plane had requested descent on passing Guernsey but disappeared from radar at about 2,300 feet.
But police finally called off the search at 15.15pm local time (10.15 a.m ET), adding they had been unable to find any trace of the plane, pilot or Sala.
"Despite the best efforts of air and search assets from the Channel Islands, UK, and France, which has covered an area of approximately 1,700sq miles -- with a significant amount of this searched more than once -- and having examined mobile phone data and satellite imagery, we have been unable to find any trace of the aircraft, the pilot or the passenger," Guernsey harbormaster Captain David Barker said in a statement.
"There has been over 24 hours of continuous searching, with 80 hours combined flying time across three planes and five helicopters. Two lifeboats have also been involved, as well as assistance from various passing ships and fishing boats.
"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."
Barker added that the next of kin had been informed.
Speaking to reporters, Barker said: "I understand that Emiliano Sala's family are not content with the decision to stop the search and I fully understand that."
He insisted that he had followed the correct protocols used by the UK Coastguard, adding: "I'm absolutely confident that we could not have done any more."
READ: Emiliano Sala's 'last goodbye' tweet gathers added poignancy
Sala was flying from Nantes to Cardiff after saying farewell to his former teammates after agreeing a $19.3 million move to the Premier League club.
Satellite imagery and mobile phone data was also being reviewed in an attempt to find the plane, police said.
Earlier in the week Barker had stated that there had been no distress call from the plane, saying "it was simply lost from radar and from communications."
Police said the plane was being flown by David Ibbotson, an experienced pilot and member of the British Parachute Association. Sala was the only passenger.
At a press conference held in Argentina on Wednesday, family spokesperson Martin Molteni told reporters that it was "essential the search continues" and that the family wanted rescuers to "use all means possible" to find out what happened.
On Wednesday it emerged that Sala sent a WhatsApp audio message to a group of friends while on board the plane.
It was unclear exactly when Sala sent the message but he describes being tired and can be heard yawning. Sala appears to joke about the aircraft, telling his friends in a deadpan tone: "I'm here on the plane and it looks like it's going to fall down in pieces." He then says that training with Cardiff would start the next day.
Near the end of the recording, he appears to make another joke, saying: "If in an hour and a half you don't have news from me... I don't know if they would send someone to look for me because they won't find me, but you will know. Dude, I'm so scared."
Throughout the message, his voice is monotone and there is no indication that his comments about the state of the plane are anything but dark humor. Sala's family spokesperson confirmed to reporters in Argentina that the message was genuine and expressed dismay that it had been made public.
A tribute to Sala was held in Nantes on Thursday afternoon with the club inviting 300 members of the public to a training session.
A portrait of the player has been placed in a street in the city, and would also soon be placed outside the stadium, to give well-wishers an opportunity to place flowers, candles and messages of support near it.
In a statement, the French club said: "The hours are long, FC Nantes continues to pray for Emiliano, just like his extraordinary determination ... The FC Nantes family is more than ever united in this event."
On Wednesday, French striker Wissam Ben Yedder paid tribute to Sala after scoring in Seville's 2-0 win over Barcelona in Spain.
The forward, who played against Sala during his time in French football, lifted his shirt while celebrating to reveal the message, "For my brother. Strength. E. Sala."
Born in Santa Fe, Argentina, Sala established his reputation in France, scoring 42 goals for Nantes since joining from Bordeaux in 2015 and particularly impressed this season.
In his most recent tweet Monday, just before he was due to fly, Sala posted a photo of himself with the Nantes FC team and the caption: "the last one, goodbye."