Petroplus, Europe's largest independent oil refiner, said on Tuesday that lenders had frozen about $1 billion in uncommitted credit lines which it said was "critical" to the company's operations.
"The company intends to continue negotiations with the banks for a prompt restoration of the credit lines, and is evaluating additional strategic options to maintain operations in its European refining and marketing system," the Swiss firm said in a statement.
Petroplus owns and operates five refineries in Europe -- the Coryton refinery in Britain, the Antwerp refinery in Belgium, France's Petit Couronne refinery, the Ingolstadt refinery in Germany and Switzerland's Cressier refinery, with a combined capacity of about 667,000 barrels per day.
The company said "approximately $1 billion in uncommitted lines" under its Revolving Credit Facility had been frozen by lenders.
"These lines are critical to allow the company's operating units to meet their obligations when due," it said.