South Korea's financial support for U.S. troops here is undervalued in Washington's estimates considering other benefits and tax breaks, a left-wing civic group claimed Monday, as a tough negotiation lies ahead amid growing pressure to raise Seoul's share.

The Solidarity for Peace and Reunification of Korea said Seoul paid 65.2 percent of U.S. Forces Korea's upkeep in 2010, which is much higher than Washington's estimate of 42 percent of the total budget, citing analysis of reports by governments of the two nations.

The latest estimate comes as the allies are preparing for talks over Seoul's burden-sharing cost for the 28,500-strong USFK as the current agreement expires at the end of this year.

According to Operation and Maintenance Overview Fiscal Year 2012 Budget Estimates, the Pentagon paid $2.7 billion for its forces in Korea.

Excluding $2 billion in payroll costs, the U.S. government paid $773 million for its non-personnel station costs, which includes management costs, family housing support and construction, and military installation and construction.

While Pentagon officials called for South Korea to increase its share for NPSC to at least 50 percent, according to a June 2012 U.S. Congressional Research Service Report, the civic group claims that the South Korean government's financial contribution combined with tax breaks and other compensation already exceeds that level.

According to a defense ministry report released by Rep. Park Joo-sun of main opposition Democratic Party, financial benefits, including indirect compensation, given by the South Korean government to USFK were estimated at about 1.6 trillion won ($1.4 billion) for 2010.

The ministry estimated the direct spending on maintaining American troops at about 856.1 billion won, and other financial benefits, including a discount rate for land use and planning and exemption from public service fees, at 818.8 billion won.

When indirect financial compensation is taken into account, Seoul's burden for American troops reaches more than 1.6 trillion won, or 65.2 percent of the total financial contribution, while the U.S. government spent 893.9 billion won, 34.7 percent, for its

troops in Korea, according to the group.

"Although the U.S. demands the South Korean government raise its financial contribution for non-personnel station costs to 50 percent from the 40-percent level, Seoul's burden already surpasses 65 percent. Therefore, the U.S. demand is unreasonable," the left-wing civic group said in a release.

(Yonhap News)