WASHINGTON (Reuters) - Haley Barbour, former Republican Party leader and Mississippi governor, has been hired by the Ukrainian government to lobby U.S. politicians, according to documents filed this week.

Haley Barbour, the former Republican governor of Mississippi, speaks at the GE conference on "American Competitiveness: What Works" in Washington February 13, 2012. REUTERS/Joshua Roberts

The hiring of Barbour and his lobbying firm BGR Group comes at a time when U.S. President-elect Donald Trump’s public embrace of Russian President Vladimir Putin has increased worries in Washington that the new administration may side with Russia in the Ukrainian dispute.

Russia has increased its military presence in Ukraine since annexing the Crimean peninsula in 2014.

Barbour and BGR agreed in late December to a $50,000 a month retainer to “design and implement a comprehensive government affairs and business development strategy” for the Ukraine government - including “arranging meetings” with U.S. officials, according to a disclosure filed Jan. 1 with the Department of Justice.

BGR also said in the federal disclosure filing that it “seeks to strengthen U.S.-Ukrainian relations and encourage private U.S. businesses to invest in Ukraine.”

American firms that do business with foreign governments are required to file disclosures with the Department of Justice detailing the work they agree to undertake and the amount of payment.

A BGR representative declined to elaborate on the specifics of the agreement.

Barbour, who served as head of the Republican National Committee from 1993 to 1997, co-founded BGR in 1991. He continued to build an expansive lobbying operation after his term as Mississippi governor from 2004 to 2012.

Barbour considered running for president in 2012, but ultimately sat out the race.

Barbour and BGR have also done work for other foreign governments, including Kurdistan, India, South Korea and Bangladesh.

Barbour’s corporate lobbying clients have included Airbus, Caterpillar, Chevron, Huntington Ingalls and Toyota Motor Corp.