WASHINGTON -- A top U.S. State Department official has warned that Russia is deepening efforts to influence Balkans politics, including encouraging the Serb-dominated part of Bosnia-Herzegovina to secede.

Speaking to a House of Representatives foreign affairs subcommittee hearing on May 17, Hoyt Brian Yee, deputy assistant secretary for Europe and Eurasia, said U.S. policy was aimed at promoting peace and stability in the region.

He said many of the Balkan nations -- Albania, Montenegro, Croatia -- are seeking even deeper integration into Western institutions such as the European Union and NATO, and Washington continued to encourage that.

Albania and Croatia are already NATO members, while Montenegro is due to join the alliance next month. Croatia is also an EU member.

Yee warned of Russia’s "malign influence" as Moscow tried to prevent that through financial and political means.

Yee suggested that a humanitarian center set up by Russia in Nis -- Serbia’s third-largest city -- may have ulterior purposes aimed at influencing public opinion.

And he said Moscow was trying to encourage the secession of Republika Srpska from Bosnia, a political arrangement that has kept uneasy peace in the country since the Dayton peace accords ended the regional war in the early 1990s.