President Nursultan Nazarbayev on Thursday returned to work in the capital Astana, the presidency said, after reports the Kazakh strongman had undergone surgery at a hospital in Germany. The Bild newspaper reported this week that the 71-year-old Nazarbayev had prostate surgery at University Medical Centre Hamburg-Eppendorf in Germany, raising concerns about a possible vacuum when he leaves power. Without referring to any leave of absence, the presidential website said Nazarbayev held a meeting on Kazakhstan\'s economic development in Astana with key ministers including Prime Minister Karim Massimov. \"Today in the Akorda (presidential palace) a working meeting chaired by the head of state Nursultan Nazarbayev took place on current questions of Kazakhstan\'s economic development,\" the presidency said. Kazakh officials did not comment on the reported treatment in Germany, saying only he was on holiday. Bild said Nazarbayev arrived in the German city of Hamburg on July 10 and was operated on by a Dutch specialist. A statement dated July 11 on the presidential website said the president was on a \"brief\" holiday. Until Thursday\'s meeting, there had been no information on the president\'s activities except for a short statement of condolence over the Volga boat tragedy in Russia. The presidency published a single photograph alongside its statement Thursday, showing Nazarbayev seated at the head of a long table with his ministers. Nazarbayev had also spoken with Uzbek President Islam Karimov to offer support after the major earthquake that killed 13 people in the country, the presidency said. Massimov provided an exhaustive list of economic statistics in the statement but no reference was made to Nazarbayev\'s absence, in a clear message that business is carrying on as normal. The president\'s health and personal life are a matter of state secrecy in the vast gas-rich nation but Nazarbayev has always sought to show a healthy image, frequently shown jogging or playing tennis. Nazarbayev\'s 10-day disappearance sparked concerns among investors over succession in the Central Asian country, which he has ruled since 1989 and is the only president post-Soviet Kazakhstan has ever known. The man most often cited as a possible successor to Nazarbayev is his son-in-law Timur Kulibayev, head of the giant Kazakh state holding company Samruk-Kazyna and husband of his middle daughter Dinara. Nazarbayev won over 95 percent in presidential elections this year but his crushing victory was marred by complaints from international observers that the elections fell well short of being free and fair. He came to power while Kazakhstan was still a Soviet republic and was elected president after it won independence. Along with Karimov, he is the longest serving leader in the former USSR. The president\'s advisors have predicted that Nazarbayev will stand again for another five year term as president in the next elections in 2016 so long as his health allows.