Royal Dutch Shell is closely watching developments at European oil refiner Petroplus
, which is closing three of its refineries after running out of money for crude supplies since bankers froze its credit lines abruptly last week.

We are permanently watching the developments at Petroplus. Due to our size in Switzerland we rely on our customers to secure supplies, Shell Chief Executive Peter Voser was quoted as saying in an interview with Swiss newspaper Sonntag on Sunday.

A victim of oversupply in European refining and of an investment strategy under former boss Thomas O'Malley that fell foul of an industry downturn, Petroplus and European government officials have been locked in talks with the 13 banks that froze a $1 billion facility it needed to buy crude oil.

The debt-laden group said on Friday it would start temporary shutdowns of three of its five refineries in January: Petit Couronne in France, Antwerp in Belgium and Cressier in Switzerland.

Petroplus also said on Friday it would continue talks with the bankers in the coming days.

(Reporting by Katie Reid; Editing by Ruth Pitchford)