Cardiff City's record signing, Emiliano Sala, was on board a flight which disappeared over Alderney, in the Channel Islands, French police sources have confirmed to AFP.
The Press Association have also received confirmation from France's civil aviation authority.
The 28-year-old Argentinian striker was signed from Nantes on Saturday and was travelling on the flight from Nantes to Cardiff.
The plane went missing near Casquets Lighthouse on Monday night, with the alarm raised at 8.23pm. Contact was lost while the plane was travelling at 2,300 feet.
Helicopters from HM Rescue have helped with the search - despite the fact the disappearance was not in the UK search and rescue area.
A spokesman said: "HM Coastguard helicopters from Solent and Newquay have been helping to search overnight with nothing found."
The search operation was impeded by worsening weather conditions throughout the night and terminated at 2am, before recommencing this morning.
Guernsey Police confirmed there were two people on board the flight.
The striker was signed for a club record fee, understood to be in the region of £15 million ($19.4m). There were initially conflicting reports in France about whether or not he was on the plane, but emerging reports which quote police sources, say this was the case - adding that Nantes defender Nicolas Pallois drove him to the airport.
Sala shared a picture on Instagram yesterday, in which he said farewell to his former teammates.
Sala said goodbye to his Nantes teammates on Instagram. Credit: Instagram/emilianosala9
The forward was due to arrive in Cardiff this week, after completing a medical in the city last week.
In a statement, Cardiff City chairman Mehmet Dalman said: "We are very concerned by the latest news that a light aircraft lost contact over the Channel last night.
"We are awaiting confirmation before we can say anything further.
"We are very concerned for the safety of Emiliano Sala."
A spokesman from Cardiff Airport confirmed the plane was bound for the city.
Airport Webcams shared a tweet which revealed the scope of the search operation.
More to follow
Featured Image Credit: Cardiff City