Giorgio Napolitano, the Italian president, expressed his condolences in a message to Juan Carlos, the Spanish king.
"At this sad moment, Italy, united with your country by traditional bonds of friendship, feels particularly close to the Spanish people," he said.
Nicolas Sarkozy, the French president, said he had learned of the "terrible" accident "with great sadness," adding that his thoughts were with the injured and the families of victims.
Dmitry Medvedev, the Russian president, also joined other European leaders in sending messages of sympathy to Spain.
"It is with deep sadness that I learnt that there had been an air accident at the airport in Madrid which ended with so many victims," Medvedev said in a message to Zapatero.