The U.S. House of Representatives unanimously approved a bill Tuesday on extending the South Korea-U.S. civilian nuclear agreement for two years.

The bill, H.R. 2449, introduced by Rep. Ed Royce (R-CA), the chairman of the House Foreign Affairs Committee, calls for a rollover of the current accord originally scheduled to expire in March next year. Under the legislation, the current "123 agreement" will be effective till March 2016.

It is intended to give Seoul and Washington more time to negotiate new rules and guidelines on their partnerships in the atomic energy sector. 

"Passage of this legislation will prevent an unnecessary interruption in nuclear energy cooperation that would have a major negative impact on the alliance and on U.S. exporters too," Royce said in a statement. "Negotiators from both countries can focus on substance instead of the clock."

The legislation now heads to the Senate for its consideration.

The allies have struggled to narrow differences on Seoul's pursuit of uranium enrichment and spent fuel reprocessing as part of its efforts to secure the stable supply of nuclear energy.

South Korean officials argue their nation needs to expand peaceful nuclear activity to meet its enhanced status as a nuclear plant exporter.

U.S. officials are apparently more concerned about the possible negative impact to the already troubled bid to denuclearize North Korea and the Barack Obama administration's global nonproliferation campaign.

South Korea's chief negotiator, Ambassador Park Ro-byug, meanwhile, plans to visit Washington late this month for talks with his American counterpart, Thomas Countryman.

Countryman, the assistant secretary of state for international security and nonproliferation, is Washington's new point man on the sensitive negotiations.

Park and Countryman will hold two days of negotiations in the final week of September, an informed source said. (Yonhap News)