Investigative Committee head Alexander Bastrykin on Thursday replaced the head of the agency's powerful Moscow branch, Anatoly Bagmet, with a little-known Kremlin administration official, marking a surprise twist in a battle between the agency and the Prosecutor General's Office.

Bastrykin appointed Vadim Yakovenko as the new head of the city's Investigative Committee, while Bagmet was named deputy head of the federal committee's main criminal department, the Investigative Committee said in a statement posted on its web site.

Yakovenko, born in 1970, worked as a prosecutor between 1994 and 2006, when he took up a job in the presidential administration, the statement said.

In the administration, he headed the department overseeing the president's annual state-of-the-nation address, a Kremlin spokeswoman said on condition of anonymity.

Yakovenko's position in the Kremlin for the past four years triggered speculation that President Dmitry Medvedev was sending an ally to one of the strongholds of the siloviki, a powerful group of former security service officials.

"The most important thing in his biography is that he worked in the presidential administration. … I think he is Medvedev's man," said Alexander Makarkin, an analyst with the Center for Political Technologies, Gazeta.ru reported.

But other analysts were more cautious. "The Kremlin is still staffed with [former President Vladimir] Putin's people," Vladimir Pribylovsky, head of the Panorama think tank, told The Moscow Times.

"All we know is that he is young and not from St. Petersburg," he added, with reference to the fact that Bastrykin studied together with Putin at Leningrad University.

Since its creation in 2007, the Investigative Committee and its boss, Bastrykin, have publicly sparred with the Prosecutor General's Office.

During his two-year tenure, Bagmet made headlines by resisting several attempts to fire him. Last December, Prosecutor General Yury Chaika tried to dismiss him for violating the oath of office.

But Bagmet said only his direct boss, Bastrykin, could fire him. Bastrykin sided with Bagmet, who subsequently won a court case against Chaika.

The prosecutor’s office earlier tried to fire Bagmet for accepting a law degree from a university in the Chelyabinsk region, where he previously worked as a deputy prosecutor.