WASHINGTON - US President Barack Obama told Russian Foreign Minister Sergei Lavrov Wednesday he supports Moscow's mediation efforts on the Libyan conflict, but on the conditions that Libyan leader Muammar Gaddafi must step down.

Repeating a position conveyed by US officials in recent days, Obama said during a White House meeting with the Russian guest he "is prepared to support negotiations that lead to a democratic transition in Libya as long as Gaddafi steps aside."

On Monday, the president had expressed a similar line in a phone call with his Russian counterpart Dmitry Medvedev, whose government remains a criticizer of the NATO-led military raid on Libya, saying it hindered the peacemaking efforts of the African Union and the United Nations.

The meeting with Lavrov also covered a wide range of other issues, including a planned missile shield in Europe, Russia's entry to the World Trade Organization, Iranian nuclear issues as well as the Sudan and South Sudan issue.

Earlier Wednesday, Lavrov said after meeting with US Secretary of State Hillary Clinton that Moscow and Washington "are united in that we have to start a political process as soon as possible."

Clinton is due to attend the so-called Libya Contact Group meeting slated for Friday in the Turkish port of Istanbul, where representatives of several Western and Arab countries and international organizations will discuss their future plans for Libya.

Meanwhile, Wednesday's The Washington Post quoted Western diplomats as saying that Gaddafi was sending fresh signals through emissaries that he was ready to discuss his departure.