MOSCOW — Pressing to mediate the Syrian conflict, Russia on Tuesday hosted the Saudi foreign minister for talks that revealed their sharp differences about the fate of Syrian President Bashar Assad.

Russian Foreign Minister Sergey Lavrov pushed for engaging Syrian government forces in international efforts to fight Islamic State militants, but his Saudi counterpart, Adel Al-Jubeir, firmly rejected any role for Assad.

"We believe that Assad is part of the problem and not part of the solution," he said.

The two did, however, agree on the need to encourage Syrian opposition groups to pool their efforts in the search for peaceful settlement.

The meeting follows Russian-Saudi talks last week in Qatar that also involved U.S. Secretary of State John Kerry. Later this week, Lavrov is also set to confer with the opposition Syrian National Coalition, which until now has refused to visit Russia.

Moscow has been a key backer of Assad, shielding his regime from U.N. sanctions and providing it with weapons throughout a civil war that has dragged on for more than four years. The conflict has left at least 250,000 dead and turned more than 4 million people into refugees.

President Vladimir Putin launched Russia's new mediation effort in June, meeting with Saudi Deputy Crown Prince and Defense Minister Mohammed bin Salman in St. Petersburg.

While details of Putin's plan haven't been made public, Lavrov said that Russia proposes to pool the efforts of all forces fighting IS, including the Syrian army, the Iraqi army and the Kurds.

Al-Jubeir insisted that the Saudi stance on the Syrian conflict has remained unchanged, adding that Assad should have no role in a future Syria.

He added, however, that he and Lavrov agreed on the need to encourage the Syrian opposition to engage in peace talks.