The ruptures on the Nord Stream natural gas pipeline system under the Baltic Sea has led to what is likely the biggest single release of climate-damaging methane ever recorded, the United Nations Environment Program (UNEP) said on Friday.

A huge plume of highly concentrated methane, a greenhouse gas far more potent but shorter-lived than carbon dioxide, was detected in an analysis this week of satellite imagery by researchers associated with UNEP's International Methane Emissions Observatory, or IMEO, the organization said.

"This is really bad, most likely the largest emission event ever detected," Manfredi Caltagirone, acting head of the IMEO for UNEP, told Reuters. "This is not helpful in a moment when we absolutely need to reduce emissions," he said.

Researchers have not yet been able to quantify from the imagery the amount of methane leaking from the pipeline system, but believe the rate of emissions is higher than from a major leak that occurred in December from offshore oil and gas fields in Mexican waters of the Gulf of Mexico, which spilled around 100 metric tons of methane per hour, Caltagirone said.

(With input from Reuters)