More than a dozen liquefied natural gas tankers are waiting their turn to fill up at Qatar’s port of Ras Laffan in a clear sign of how tight the global gas market has become.

South Korean and Pakistani buyers are among those seeking to maximize shipments under long-term supply contracts with the Middle Eastern emirate, one of the world’s biggest natural gas exporters, according to traders with knowledge of the matter. The cargoes are linked to oil prices and cost about half of the current rate in spot gas markets, where a global supply crunch has seen prices rise to seasonal highs.