(CNN)A Eurofighter jet has crashed, killing its pilot, as it was returning to a military base in Spain's southeast on Thursday, the country's air force said.
The aircraft had been involved in a military display in Madrid during National Day celebrations and was on the approach to the Los Llanos Air Base on the outskirts of Albacete.
"As a result of the accident, which happened while maneuvering for landing, the pilot of the aircraft has passed away," the Spanish Air Face confirmed in a series of tweets from their official account.
First responders attended the scene on farmland near the base after receiving a call around midday local (7 a.m. ET), Reuters reported.
The cause of the crash was unclear and the Ministry of Defense has launched an investigation, the air force added.
Prime Minister Mariano Rajoy offered his condolences to the pilot's family on Twitter and said that he was en route to the site of the accident with the Spanish Minister of Defense, Maria Dolores de Cospedal.
Madrid deadline looms
Spain marked its national day this year amid a backdrop of political chaos, with the semi-autonomous region of Catalonia threatening to break away.
After a disputed October 1 referendum to determine if the region should split from Spain, Catalan President Carles Puigdemont signed what appeared to be a symbolic declaration of independence on Tuesday.
A day later, Rajoy said the Catalan leader had until 10 a.m. local time Monday to confirm whether the Catalan parliament had declared independence.
Rajoy warned in the letter that if the answer was yes, and Puigdemont refused to withdraw the declaration by the following Thursday, he could impose direct rule under article 155 of the Spanish constitution.