ASTANA: Kazakhstan's President Nursultan Nazarbayev on Friday signed an order to hold snap presidential elections on April 3 after rejecting a referendum on prolonging his rule until 2020.

The presidential decree was cited by the Interfax-Kazakhstan news agency.

Nazarbayev, whose current term is due to expire in 2012, on Monday unexpectedly rejected the plan to hold a referendum and said he would instead call early presidential polls.

The presidential announcement to reject the referendum plan, which had envisaged scrapping elections in 2012 and 2017, came after rare criticism of the ex-Soviet state by its Western ally the United States.

The parliament last month said the controversial referendum should go ahead but the constitutional court later rejected the plan.

US State Department called the move to jettison the referendum plan "the right decision" but critics say that Nazarbayev's announcement to call snap elections instead is largely designed to pacify the West.

Few doubt that Nazarbayev will secure an overwhelming victory in the polls and analysts say the opposition, which was caught off guard by the announcement, would simply not have enough time to prepare for the polls.

The 70-year-old leader has ruled Kazakhstan, Central Asia's largest oil producer and one of the world's leading uranium producers, since it became independent from the Soviets.

Along with Uzbek President Islam Karimov, who rose to power at the same time, Nazarbayev is the longest-serving leader in the former Soviet Union.