Iraqi security forces said they advanced to within 2 km (1.2 miles) of the city of Baiji on Wednesday in a new offensive to retake the country’s biggest oil refinery, besieged since June by Islamic State militants.

Backed by Shi’ite militias and army helicopters, government forces have swept through a desert area to the west of Baiji, aiming to recapture the city 200 km (130 miles) north of the capital.

They hope to cut off supply lines to militants encircling the refinery and gain control of a road leading to Mosul, the biggest city in the north, an army colonel told Reuters. […]