The U.S. government is reported to have granted a sanctions exemption to allow the two Koreas to conduct a survey on reconnecting railways across their border. 

Multiple government sources in Seoul said Sunday, Washington gave its exemption after the U.S. and South Korea's recently-launched working group meeting between their chief nuclear envoys in Washington last week.

Seoul had required Washington's exemption for deliveries of fuel and materials consisting of at least ten percent of U.S.-made parts and technology to conduct the survey in the North.

Pyongyang is under heavy UN and U.S.-led sanctions, including capped imports of refined petroleum, for its nuclear weapons and ballistic missile programs.

The UN Security Council on Friday granted its sanctions exemption, paving the way for the survey and a groundbreaking ceremony before the end of the year.