U.S. President Barack Obama adjusts his translators ear piece as he listens to Russian President Dmitry Medvedev during their joint news conference at the Kremlin in Moscow July 6, 2009. Visiting Obama and Kremlin leader Medvedev agreed a target for cuts in nuclear arms and a deal to let U.S. troops fly across Russia at the start of a trip intended to mend strained ties. REUTERS/Jason Reed

MOSCOW (Reuters) - In a slip of the tongue, U.S. President Barack Obama described Prime Minister Vladimir Putin on Monday as president, echoing the widely held view that he remains Russia’s most powerful man.

Putin surrendered the presidency to protege Dmitry Medvedev last May to take the lesser post of prime minister, but most political analysts say Putin remains Russia’s ultimate decision maker.

The dual leadership has left foreign leaders to walk a difficult diplomatic tightrope. In line with protocol Obama met Medvedev ahead of talks with the lower ranking Putin.

At a news conference Obama gave a carefully worded reply about the effectiveness of the leadership tandem when a U.S. journalist bluntly asked “who is really in charge here in Russia?”

But minutes later, speaking about Medvedev’s objections to a controversial missile defense system planned for central Europe, Obama slipped:

“I suspect when I speak to President..eh.. Prime Minister Putin tomorrow, he will say the same thing.” (Writing by Conor Humphries; Editing by Richard Williams;)