Dandong, China ? Ahead of the adoption of a U.N. Security Council resolution against Pyongyang, China increased security along its border with North Korea by building fences in and near Dandong, its largest city on the border.

Residents on both sides of the border seemed unable to quell anxiety about the situation, as some North Korean merchants began stockpiling goods.

Even after Pyongyang’s announcement that it conducted a nuclear test, areas along the border appeared calm. But a drive closer to the border, about 12 miles north of central Dandong, revealed brand-new barbed-wire fences.

Near the fences the width of Yalu River, which forms the border between China and North Korea, is less than 33 feet, which means crossing the river is relatively easy.

A nearby resident said, “The fences were built a week or so ago, though we don’t know why.”

Locals said the fences seem to be designed to prevent North Koreans from illegally crossing the border into China.

Beyond the river, North Korean farmers working with tractors in fields could be seen. Before, houses lined the North Korean side of the river.

A newly erected fence constructed by the Chinese divides the border it shares with North Korea near the Chinese city of Dandong. The fences are intended to prevent North Koreans from fleeing across the border.

A Chinese source in Dandong said, “About 150 households were forcibly moved from the border area to a remote location.”

A merchant in Dandong who trades between China and North Korea said even after the U.N. resolution condemning Pyongyang, “It is unlikely that the movement of daily goods and food (for North Korean citizens) will be adversely affected.”

However, a border guard official in Dandong told Asiaweek, a Hong Kong news magazine, that it was possible at least 500,000 North Korea refugees could flow into Liaoning and Jilin provinces, which border North Korea.

The official predicted this could happen if food and daily necessities from China to North Korea are stopped for a long time due to closure of the border or other incidents.