Several large oil companies are shutting down operations in Egypt as six days of protests against President Hosni Mubarak's regime have disrupted the oil and gas industry.

The nation's military closed ranks with the government leadership but allowed protestors to continue mass demonstrations in defiance of a curfew as further unrest spread through the streets of Cairo. Mohamed ElBaradei, the former head of the United Nations' nuclear watchdog agency, has emerged as the favorite among opposition leaders to replace Mubarak.

Statoil ASA (NYSE ADR: STO), Norway's largest oil company, halted drilling in Egypt as other companies, including Royal Dutch Shell PLC (NYSE ADR: RDS.A, RDS.B) and BP PLC (NYSE ADR: BP), shut down local offices and started evacuating the families of expatriate workers as well as non-essential staff.