Chernomyrdin's appointment is believed to be a strategic move by the president to clip the wings of Primakov, whom the United States considers an ``unfriendly'' person striving to revive the Soviet power.

Chernomyrdin, on the other hand, is seen as a statesman enjoying trust of the west and expected to buy a cease-fire for Yugoslavia, observers say.

The move comes barely a day after the president failed to rein in Primakov to persuade the Duma to declare a final verdict on impeachment against him immediately, news agency Novosti reports.

The Russian executive and legislature went into a fresh stand-off yesterday with the Duma deciding to begin impeachment proceedings against Yeltsin from May 12-15 ignoring his pleas for an immediateverdict.

According to Kremlin sources, an immediate verdict in the Duma would have gone in favour of the president whereas the `open ballet' during the May session increases the chances of Yeltsin being removed from office.

The Duma's move comes after Yeltsin tried unsuccessfully to put pressure on Primakov -- who enjoys support of the Communist-dominated Duma -- to achieve good results, Voice of Russia reported.

``Though you are good at present, you are on probation,'' the president told Primakov, who repeated it word by word in a televised address to the nation. Yeltsin was forced to call his premier for a tete-a-tete, the report said.

Irked by the Duma's stand, Kremlin sources told Novosti today that if parliament decides to confront the president, it would have no reason to keep two Communist leaders in the Primakov cabinet.

The presidential administration has been training its guns on First Deputy Premier Yuri Maslyukov and Deputy Premier Gennadi Kulik, believed to bepro-Communists.

Primakov, who banks on the vast experience of his deputies in running the economy during Soviet times, had made it clear that removal of his colleagues would mean his leaving the office.

Yeltsin's decision to divest Primakov of Yugoslav affairs and hand it over to Chernomyrdin has sparked speculation in political circles that the latter is on his way back to being premier, a position he occupied twice.

There had been reports of frequent meetings and telephonic talks between the president and Chernomyrdin. If the west agrees to Russia's proposals to stop air raids on Yugoslavia and enter into a dialogue with Serbian leaders, it would pave the way for Chernomyrdin's return to power, political analysts say.