Russia's largest oil company, Lukoil, has offered a 30 million roubles ($948,000) reward for information leading to the release of one of its top executives, who was kidnapped on Thursday.

Unfortunately in Russia today, no matter how high a post this or any other person occupies, they can't feel safe

Vagit Alekperov, Lukoil's President

Sergei Kukura - one of Lukoil's vice-presidents responsible for its finances - was on his way to work in the capital, Moscow, when his Mercedes was stopped by a group of men with Kalashnikov rifles, a company statement said.

The attackers handcuffed his driver and bodyguard and drove Mr Kukura away in a car with blue plate numbers, usually used by police vehicles.

Russian police - together with the Federal Security Service - have launched a massive manhunt.

Mr Kukura had access to "confidential information"

On Friday, Lukoil's President Vagit Alekperov said the abduction had inflicted "great trauma" on the company and warned that Lukoil would do everything to find the attackers.

"The kidnappers should know that we will spare all efforts and as much time as necessary to make sure they get a severe punishment," he said in a statement.

The BBC's James Schofield in Moscow says that while contract killings are common in Russia, the kidnapping of such a senior official is unprecedented and a blow to President Vladimir Putin's efforts to clean up the country's image.

Low profile

Mr Kukura, who has held his current post since 1996, is a top petroleum expert and had access to "confidential information, including state secrets," according to Lukoil.

Alekperov is taking extra security measures to protect Lukoil's staff

As chief financial officer at Lukoil, Mr Kukura is a powerful figure and is said to be immensely rich.

But our correspondent says he maintains a low profile and is not involved in politics. He also plays no significant role in other businesses.

Lukoil accounts for more than 20% of Russia's oil exports; the state owns about 14% of the company.