Kazakhstan's Prime Minister Serik Akhmetov, who had managed Central Asia's largest economy since September 2012, said on Wednesday that he had resigned, according to Reuters.

There was no immediate indication why he stepped down, but President Nursultan Nazarbayev, who wields sweeping powers in his vast nation, can change prime ministers at his own choosing.

Journalists summoned to government headquarters saw Akhmetov on monitors, telling a cabinet meeting that had Nazarbayev accepted his resignation.

Akhmetov, 55, is a devoted loyalist of Nazarbayev. He started his career at the same steel plant in Temirtau as the president and later rose through the ranks of the Soviet Communist party.

He said that under the law his cabinet had resigned with him, but the ministers would continue carrying out their duties before a new government is formed.

"I hope that this composition of the government will be mainly preserved and will continue working for the future of our motherland," Akhmetov told the cabinet, according to Reuters.

His successor will face a major task of preparing Kazakhstan's integration into the Eurasian Economic Union which will unite Russia, Kazakhstan and Belarus. The union, to be formed by 2015, is widely seen as a regional counterbalance to the European Union.

Kazakhstan is the second-largest post-Soviet oil producer after Russia.