Kazakhstan's Prime Minister Daniyal Akhmetov is shown at Prime Minister Junichiro Koizumi's official residence in Tokyo in this 14 June 2005 file photo

Officials in Kazakhstan say Prime Minister Danial Akhmetov has resigned.  There was no explanation for the move.

Mr. Akhmetov, who headed the country's cabinet since 2003, Monday offered his resignation to President Nursultan Nazarbayev, the powerful leader who has run Kazakhstan since the 1991 break-up of the Soviet Union.  Mr. Akhmetov will be replaced by Deputy Prime Minister Karim Masimov.

Kazakh officials released few details about the resignation, but analysts say President Nazarbayev often replaces senior officials for his own reasons.

Kazakhstan, in Central Asia, is rich in oil and gas and is one of the most economically successful post-Soviet nations, with large investments by Western energy companies.

The country has been criticized for a lack of economic transparency.

Some information for this report was provided by AFP, AP and Reuters.