Kazakh President Nursultan Nazarbaev has dismissed his chief of staff, replacing him with the mayor of the capital, Astana.
Adilbek Zhaqsybekov, 64, was dismissed because he had reached retirement age, Nazarbaev's office said on September 10
It said 47-year-old Aset Isekeshev will take up the chief of staff position.
Nazarbaev has yet to name his replacement as Astana mayor.
Isekeshev previously served as a government minister overseeing industry and foreign investments.
Zhaqsybekov served as Nazarbaev’s chief of staff from 2004 to 2008 and was reappointed in 2016.
A long-time loyalist to Nazarbaev, he is also a former prime minister, defense minister, and minister of industry and trade.
His family controls several large businesses, including Tsesnabank, Kazakhstan's second biggest lender by assets.
Corporation Tsesna, a holding company for those businesses, said on September 10 that Zhaqsybekov became its chairman.
Nazarbaev, 78, has been in power in the energy-rich Central Asian country since before the Soviet Union collapsed in 1991.
He was last elected in 2015, securing a new five-year term after moving the vote up from 2016 in what was widely seen as a move to strengthen his control.
Rights activists and critics say he has persistently suppressed dissent, prolonged his time in office through undemocratic votes, and used the levers of power to neutralize potential opponents.