Moscow - US President Barack Obama met Tuesday with Russian Prime Minister Vladimir Putin on the second day of his visit to Russia.

Among the topics the two leaders were expected to discuss was the US missile defence shield in Eastern Europe, which Russia has criticized.

Obama said he and Putin believed their talks were an excellent opportunity to set US-Russian relations on a firm foundation as the discussions were getting under way at Putin's residence outside Moscow.

Putin, who many analysts believe still holds the reins of power in Russia after giving up the presidency in May 2008, said Obama's name is tied to hopes for an improvement in bilateral ties, which had turned frosty under Obama's immediate predecessor, George W Bush.

The Russian premier admitted that US-Russian ties had experienced good as well as difficult phases.

On the first day of his trip, Obama met with Putin's successor, President Dmitry Medvedev. The two hailed a "fresh start" in their countries' relations and reached a basic agreement that there must be a follow-up treaty to the START disarmament pact, due to expire at the end of the year.

They also agreed on Russia letting the United States use its airspace for military transports in operations in Afghanistan.

The main step announced by Obama and Medvedev was a "joint understanding" that aims to reduce the number of nuclear warheads held by each to between 1,500 and 1,675, compared with the current START (Strategic Arms Reduction Treaty) maximum of 2,200.

They would also aim to reduce the number of rockets capable of delivering the warheads from the current maximum of 1,600 allowed for each side to 500 to 1,100.