MOSCOW - RUSSIAN Prime Minister Vladimir Putin was on Thursday to give a keynote address to his party congress as speculation mounted he is planning a presidential comeback amid a growing financial crisis.

His speech at a congress of the ruling United Russia party will be closely watched for hints about his political future and comments about the financial crisis, which threatens to weaken the Kremlin's grip on power.

The congress was to open in Moscow at 0900 GMT (5pm Singapore time), one day after the lower house of Russia's parliament overwhelmingly approved a bill extending the presidential term from four years to six, in the second of three required readings.

The changes have sparked fresh speculation that President Medvedev, who succeeded Mr Putin as president in May, could use the pretext of constitutional changes to step down early and make way for a return to the post by his mentor.

Both men have played down such claims without rejecting them outright.

Mr Putin's speech comes as financial turmoil has ravaged Moscow's stock markets and plunging oil prices have slowed growth, threatening the economic stability seen as one of the main accomplishments of his eight-year presidency.

The crisis will be discussed at Thursday's party congress, which Mr Putin is chairing, said Mr Boris Gryzlov, one of United Russia's leaders and a key Putin ally in parliament, in comments posted on Wednesday on the party's website.

Mr Gryzlov said Mr Putin would report on the country's development to 2020 under what is called the 'Putin Plan, a Worthy Future for a Great Country.' But he added that 'in the current situation there have arisen problems, questions about how to realise the strategy in the conditions of the global financial crisis.' He also confirmed that Mr Medvedev would attend the congress, without clarifying the president's role. It was not clear at what time Mr Putin's speech was to start once the congress is underway.

Various developments and media reports this week have prompted speculation that Mr Putin is seeking a return to the Kremlin.

On Tuesday, Mr Putin's spokesman said he would continue his presidential tradition of holding a televised phone-in session with the Russian people this year, further reinforcing the impression he is still the de-facto leader.

Meanwhile, citing unnamed Kremlin sources, the Russian edition of Newsweek reported that Mr Putin was planning to surrender the premiership and return to the presidency for two more six-year terms.

It said that 'firm and unpopular' measures were required at a time of mounting turmoil over the economy and it should be the job of a more technocratic prime minister to take them, rather than Mr Putin.

Deputy Prime Minister Igor Shuvalov had already discussed with Mr Putin the possibility of succeeding him, Newsweek said.

Not all experts are convinced however that Mr Putin is set to make a dramatic return to the Kremlin or that Mr Medvedev would leave so easily.

'Medvedev is no longer a puppet of Putin but a real actor,' said analyst Yuri Korgunyuk of the Indem foundation. -- AFP