Car users in Pyongyang are scrambling to fill up their tanks as gas stations began limiting services or even closing amid concerns of a spreading shortage.

A sign outside one station says sales are being restricted to diplomats or vehicles used by international organizations, while others were closed or turning away local residents.

The cause of the restrictions or how long they might last was not immediately known.

North Korea relies heavily on China for its fuel supply and Beijing has reportedly been tightening its enforcement of international sanctions aimed at getting Pyongyang to abandon its development of nuclear weapons and long-range missiles.

The issue was raised at a regular Chinese Foreign Ministry briefing in Beijing on Friday but spokesman Lu Kang gave an ambiguous response.