FRANKFURT- Construction work on the Nord Stream 2 gas pipeline could be halted for an indefinite period of time in German waters, the country's Federal Maritime Authority BSH said on Thursday.

Two environmental groups earlier this week filed complaints with BSH against a move to expand the period during which construction work can theoretically take place.

(Reporting by Christoph Steitz, editing by Kirsti Knolle) ((christoph.steitz@thomsonreuters.com; +49 30 220 133 647;))