The private plane crashed near the city of  Ventspils off the coast of Latvia on Sunday September 04, 2022.
CNN  — 

A private jet crashed into the Baltic Sea off the coast of Latvia on Sunday, hours after NATO jets were scrambled to follow the plane.

The Austrian-registered Cessna Citation 551 departed Jerez, Spain at 12:56 UTC (8:56am ET) and its intended destination was Cologne, Germany, according to Flightradar24, a website which monitors global air traffic.

But it came down in waters near the city of Ventspils in Latvia, according to Latvia’s defense minister and deputy prime minister Artis Pabriks, who said the Latvian military was deployed in a search and rescue operation.

The aircraft was certified for single-pilot operations, according to German newspaper Bild, which reported that the plane had four people on board, including the pilot, a man, a woman, and a person Bild described as a daughter, without providing further details.

A file photo of a Cessna 551 Citation II/SP, similar to the aircraft that crashed, pictured at Dusseldorf Airport in Germany in 2021.

“Jets from NATO allies and partners were scrambled to follow the private Cessna plane which crashed on Sunday evening off the Latvian coast. They included German planes from Neuburg and Laage in Germany, and German and Spanish planes, part of NATO Baltic Air Policing, from Ämari, Estonia. France, Denmark and Sweden also scrambled jets under national command, a NATO official told CNN.

“The pilots were unable to contact the plane and could not see anyone in the cockpit,” the official added.

Flightradar24 said “the pilot didn’t answer ATC calls and the aircraft continued to fly on autopilot in a straight line before it lost altitude and crashed.”

The “final altitude received was 2100 ft at -8000fpm descent,” before the transponder signal from the aircraft stopped being received by tracking site.

French aviation police, which also intercepted and escorted the jet, were alerted by Spanish authorities “of probable difficulties of pressurization of the aircraft,” the French armed forces ministry said in a statement.

Attempts by French authorities to contact the jet were unsuccessful but the unresponsive aircraft “was continuously escorted during its transit towards Germany,” the ministry added.

Latvia said it had sent ships to the scene.

Lars Antonsson of Sweden’s Maritime and Air Rescue Centre told CNN affiliate Expressen that a Swedish helicopter as well as an airplane took part in the rescue operation in Latvian waters after the plane flew over the Swedish island of Gotland.

Antonsson said search teams had located parts of the plane, but “no survivors have been found.”