Nantes - Cardiff City's record new signing Emiliano Sala expressed concern about his plane shortly before the light aircraft disappeared over the Channel, according to an audio message sent to friends and relatives.

The Argentine striker, signed on Saturday from French club Nantes for a reported fee of €17 million, was flying to Cardiff aboard the plane that disappeared from radar around 20 kilometres (12 miles) north of the island of Guernsey on Monday night.

"I'm on a plane that looks like it's going to fall apart, and I'm leaving for Cardiff," Sala said in a WhatsApp audio message carried by Argentine media.

"If in an hour and a half you have no news from me, I don't know if they will send people to look for me, because they will not find me, you know. Dad, I'm so scared," he added.

Sala is missing presumed dead after the single-engine Piper PA-46 Malibu aircraft disappeared.

A 15-hour search Tuesday covering a 1,155 square-mile (3,000 square-kilometre) area in the Channel spotted "a number of floating objects in the water", Guernsey police said.

"We have found no signs of those on board. If they did land on the water, the chances of survival are at this stage, unfortunately, slim," police said.

The search was set to resume at sunrise Wednesday.

French civil aviation authorities had confirmed that 28-year-old Sala "was on board the plane". It is thought there was one other passenger on the aircraft.

Police on Guernsey, which sits just off the north coast of France, said the pilot had requested to lower his altitude shortly before air traffic control in neighbouring Jersey lost contact with the plane.

'Fearing the worst'

One of the rescuers searching for the missing plane earlier admitted they were "fearing the worst", thoughts echoed by Sala's father Horacio.

"Sadly we are fearing the worst... the sea temperature is so cold at the moment," John Fitzgerald, chief officer of Channel Islands Air Search, told AFP.

A tearful Horacio Sala told the press in Progreso, where the player's family lives, that as "the hours go by and I don't know anything, it makes me fear the worst".

"I don't know anything. Nobody spoke to me, not a call from the embassy, the club, nobody," he said. "All I want is for you to find him."

The player's mother, Mercedes, claimed in an interview with Argentine television channel C5N that the plane belonged to Cardiff chairman Mehmet Dalman.

Sala, who had been at Nantes since 2015 and had scored 13 goals in all competitions this season, had signed a three-and-a-half-year contract with relegation-threatened Cardiff subject to receiving international clearance.

"We were very shocked upon hearing the news that the plane had gone missing. We expected Emiliano to arrive last night into Cardiff and today was due to be his first day with the team," the Premier League club's executive director Ken Choo said in a statement.

"We continue to pray for positive news."

Argentine football legend Diego Maradona expressed sadness but said he was hoping the plane had simply gone astray.

"I hope it went to the wrong airport and we find him alive, that's all," he said in an audio message on the Instagram account of journalist Martin Arevalo.

"It's a terrible misfortune when such things happen."

Cardiff called off a training session planned for Tuesday, and stunned supporters gathered outside the club's ground to lay flowers and scarves.

With his former teammates in shock, Nantes had their French Cup tie against third-tier side Entente Sannois Saint-Gratien postponed from Wednesday until Sunday.

Fans hold vigil

Meanwhile, hundreds of fans of his former team gathered for a vigil in the western French city on Tuesday evening, placing flowers, scarves and flags on the water fountain and chanting the striker's name at Place Royale.

"I still have hope, he is a fighter," said Nantes president Waldemar Kita in a tweet published by the Ligue 1 club.

When he put pen to paper at relegation-threatened Cardiff on Saturday, Sala, who also has Italian nationality, said in a statement: "I'm very happy to be here. It gives me great pleasure and I can't wait to start training, meet my new team-mates and get down to work.

"For me it feels special (to be the club's record signing). I have come here wanting to work and to help my team-mates and the club."

Sala's last post on Instagram showed him surrounded by players from Nantes. "La ultima ciao (the last goodbye)," he wrote.

Sala began his footballing career at French club Bordeaux, who he joined in 2010, and had loan spells at other French clubs including Orleans, Niort and Caen.

He joined Nantes in 2015 for one million euros and had scored 42 Ligue 1 goals in three and a half seasons at the Stade de la Beaujoire.