Saudi security forces have stormed an expat housing complex where suspected Islamic militants are holed up with a reported 50 hostages after attacking oil company offices.

Saudi security forces stormed a prestige expatriate housing complex where gunmen holed up and took hostages after a shooting dead at least six people at oil company offices in the eastern city of Khobar.

The Footsie index of 100 leading stocks is ahead 12.8 points at 4708.9 at lunchtime.