FRANKFURT, Jan 19 (Reuters) - German construction and engineering group Bilfinger has withdrawn from work related to the construction of the Nord Stream 2 gas pipeline, German tabloid Bild reported on Tuesday, citing letters it has obtained.

Concerned over looming U.S. sanctions targeting companies associated with the project, Bilfinger has recently informed the United States as well as Nord Stream 2 AG, a subsidiary of Russia's Gazprom, about the decision.

Bilfinger had been contracted to develop, deliver and operate process control and safety systems for the controversial pipeline as well as supply a gas-fired heating generation unit, Bild reported.

A spokeswoman for Bilfinger declined to comment.

The news comes as the U.S. Treasury Department on Tuesday slapped sanctions on a vessel helping to build the pipeline to take Russian natural gas to Europe via Germany. (Reporting by Christoph Steitz; editing by Thomas Seythal)