Vladimir Putin, a loyal Yeltsin supporter, described his main task as "improving the life of the people."
A seasoned spy with little political or economic experience, Vladimir Putin vaulted to Russia's No. 2 spot Monday when Boris Yeltsin appointed him acting prime minister.
His espionage background seemed to be a key selling point. Yeltsin's last two prime ministers, Sergei Stepashin and Yevgeny Primakov, also worked for Russian intelligence agencies.
Putin, a 46-year-old with ramrod-straight posture, is seen as tougher than mild-mannered Stepashin, which appeals to Yeltsin and his inner circle as they prepare for a bruising battle in December parliamentary elections and presidential elections next summer.
Yeltsin, who is constitutionally barred from running for a third term, openly anointed Putin as his preferred successor Monday, and Putin immediately announced he would run for president.
"Perhaps I have little experience as a politician," Putin acknowledged when asked why he made the announcement so soon. "I did not engage in politics."
Putin's limited political experience makes it hard to judge what kind of prime minister he will be, much less president. Besides, an endorsement from the extremely unpopular Yeltsin may be a mixed blessing.
Putin "is a bureaucrat rather than a national leader," said Yevgeny Volk, a political analyst with the conservative Heritage Foundation. "He has no charisma."
Former colleagues described Putin as "secretive" and "closed," and he accepted his appointment Monday in a terse, matter-of-fact fashion.
"We are military men, and we will implement the decision that was made," Putin told reporters as he sat at his Kremlin desk, topped with six telephones adorned with the old Soviet state emblem.
Speaking later on Russia's NTV network, Putin mentioned his doctoral thesis in economics and promised "no revolutionary changes" from the economic course of the previous Cabinet. He did, however, speak vaguely about increasing the government's regulatory role.
Putin described his main task as "improving the life of the people, the population's standard of living" _ yet also issued a harsh warning to those who might be planning labor unrest, which in the past has involved railroad blockades.
"Those who destabilize the situation will sit (in jail)," Putin said.
In his rare public remarks before the appointment, Putin has stressed the need for Russia to rebuild the security services that have been undermined by the country's general decline and chronic money problems since the Soviet breakup in 1991.
Putin, who likes such martial arts as judo and the Soviet-devised sambo, is considered extremely loyal to Yeltsin. But so was Stepashin, whom Yeltsin fired Monday without giving a reason.
Immediately after graduating from the law faculty at Leningrad University in 1975, Putin began a 15-year career with the KGB's foreign intelligence arm, including a posting as an agent in Germany.
After retiring from the KGB with the rank of colonel, he began working in St. Petersburg's local government, rising to the post of vice mayor in 1994.
Yeltsin brought Putin to Moscow in 1996, naming him deputy chief Kremlin administrator. Since then, Putin has also served as the Kremlin official in charge of relations with Russia's far-flung regions and last year was named head of the Federal Security Service, the KGB's main successor agency.
In March, Putin was also named secretary of the presidential Security Council, a powerful advisory body that coordinates activities of the armed forces, security agencies and police.
He is married and has two school-age daughters.
"I'm convinced that he will serve the nation well," Yeltsin said in a television address.