Total capacity of the two lines is 55 billion cubic metres per year. The consortium said a piece of munitions was found in close proximity to the Nord Stream Line 2 on Nov. 6.
"The location of the object is in the Swedish Exclusive Economic Zone (EEZ) approximately 120 km away from the island of Gotland," Nord Stream said.
It added that it was not clear when the gas supplies via the line would be resumed.
It said the Swedish armed forces were on site to "safely and professionally dispose of the munitions object".
"They have to work under windy conditions, so there is no set timeline when the works will be completed".
Swedish media reported that a remote-controlled device designed to remove undersea mines was found near the pipeline. Some mines have been left in the area since the World War Two.
(Reporting by Vladimir Soldatkin, editing by David Evans)