MADRID, Nov 27 (Reuters) - Spanish lender Sabadell has given Goldman Sachs a mandate to sell its loss-making British unit TSB, a source aware of the mandate told Reuters on Friday.

The source said that the process was under way and that Goldman Sachs, which had been hired by Sabadell in July to explore various options, had now been tasked with the sale of TSB.

The source did not provide any more details or a timetable of its planned divestiture.

Both Sabadell and Goldman Sachs declined to comment.

Sabadell and its bigger rival BBVA earlier on Friday announced they had called off merger talks.

Sabadell said in a press release after the merger talks were called off that it would now analyse "strategic alternatives" for its international assets, including TSB, which it bought in 2015, without elaborating further. (Reporting by Jesús Aguado; editing by Ingrid Melander)