NUR-SULTAN/ALMATY • Kazakhstan's interim president Kassym-Jomart Tokayev, the chosen successor of veteran ruler Nursultan Nazarbayev who retains sweeping powers, has won a snap presidential election which observers say was tarnished by violations of basic freedoms.

Mr Nazarbayev, who ruled oil-rich Kazakhstan for almost three decades, handpicked the 66-year-old Mr Tokayev, a career diplomat, as his successor when he stepped down in March.

In a power-sharing arrangement, Mr Nazarbayev, 78, remains chairman of the influential Security Council of Kazakhstan and leads the ruling Nur Otan party.

With Mr Tokayev winning nearly 71 per cent of the vote in a race against six rivals who are largely unknown to Kazakh voters, opponents have denounced the election as unfair, prompting public protests despite Kazakhstan's restrictive laws on freedom of expression.

Election observers from the Organisation for Security and Cooperation in Europe said "a lack of regard for fundamental rights, including detentions of peaceful protesters, and widespread voting irregularities on election day showed scant respect for democratic standards".

The observation mission added: "At the same time, irregularities on election day and a disregard of formal procedures meant that an honest count could not be guaranteed."

During Sunday's vote, the police arrested 500 people at rallies in Almaty and Nur-Sultan, the capital city previously known as Astana, which was renamed after Mr Nazarbayev at Mr Tokayev's suggestion.

Deputy Interior Minister Marat Kozhayev blamed "radical elements" for holding "unsanctioned" rallies.

Activists denounced the arrests while there also were claims of ballot stuffing, but Mr Tokayev insisted that the election had been "a competition".

"This shows that our level of political culture has seriously increased. There is much work ahead," he said in comments broadcast on state television yesterday.

The authorities said they would investigate all allegations of vote violations.

Yesterday, the number of protesters was much smaller as hundreds of policemen gathered at the Almaty park where Sunday's rally took place. A Reuters correspondent saw the police detain a few dozen people.

The Kazakh state closely controls domestic politics and public discourse. The vast majority of the local media does not criticise Mr Nazarbayev, and social media as well as online messaging platforms were restricted during Sunday's election.

In March, Mr Nazarbayev's eldest daughter, Ms Dariga Nazarbayeva, became Speaker of the Senate, the post previously held by Mr Tokayev. Members of the former president's family control some key business assets such as Kazakhstan's largest bank, Halyk.