The United States hit out Wednesday at Russian troops' efforts to build a de facto border in the breakaway Georgian regions of Abkhazia and South Ossetia.

"We note with concern the continued and increasing activities by Russian security forces to erect fences and other physical barriers along the administrative boundary lines of the occupied territories in Georgia," US State Department deputy spokeswoman Marie Harf said.

"This borderization is inconsistent with Russia's international commitments and Georgia's sovereignty and territorial integrity within its internationally recognized borders.

"We would call on the Russian Federation to remove the barriers and to address issues related to the conflict in Georgia at the Geneva international discussion."

Abkhazia declared independence from Georgia following a brutal war in the early 1990s.

South Ossetia and Abkhazia are recognized only by Russia and a few far-flung states.

Russia -- which fought a brief war with Georgia in 2008 over South Ossetia -- has several thousand troops stationed in Abkhazia and South Ossetia.

Last month, Georgian Foreign Minister Maia Panjikidze told the UN Human Rights Council in Geneva that Russia was waging an "occupation" in the regions.

She said Russian forces were engaged in a "massive process of installation of barbwire fences and embankments along the occupation line," in breach of international law.