The South Korean government held a working-group meeting with U.S. officials in Washington D.C. last Tuesday and promised to conduct the survey in a manner that does not violate sanctions against the North.

The UNSC's sanctions committee on North Korea, which made the decision, consists of 15 member nations and a unanimous decision is required for an exception.

The UN Security Council has given South Korea the green light to survey sections of North Korea's railroads that are to be connected with the South. The exemption from international sanctions applies only to the survey, not actual repairs until North Korea scraps its nuclear weapons.

The measure is thought to be a nudge to get North Korea to resume high-level talks with the U.S., which Pyongyang called off on Nov. 8. "The U.S. found it hard to refuse a railroad survey that an ally was seeking," a diplomatic source in Washington said. It "appears to have allowed the survey to draw North Korea back to the negotiating table."

Seoul believes it can wrap up the survey by the end of this year if it gets started within this month. But actual work to modernize the decrepit railways will have to wait.

South Korea will start negotiations with North Korea this week over the scheduling. A government source said, "It should be possible to start the joint survey this week." Oil and other supplies necessary for the survey can now be brought into North Korea despite the sanctions. That includes equipment containing more than 10 percent of U.S. components. Seoul hopes to wrap up the survey in two to three weeks.

Cheong Wa Dae welcomed the decision, but it suggests that inter-Korean projects require U.S. approval at each stage.

The UN Command, which is headed by the U.S. Forces Korea commander, refused to authorize the survey in late August. The Unification Ministry said at the time that survey should not be subject to sanctions, but continued problems in gaining approval prompted it to seek UNSC authorization.

Shin Beom-chul at the Asan Institute for Policy Studies said, "The survey of inter-Korean railway projects and the following ground-breaking ceremony are not huge violations of sanctions and could have begun if there had been prior consultation with the U.S. But the U.S. will increase its calls for denuclearization if the project is to progress to the next stage."