ExxonMobil and Royal Dutch Shell, the two biggest western oil companies, on Thursday won the right to develop Iraq’s giant West Qurna oilfield, raising the prospect of a big jump in Iraqi oil supplies.

The agreement is the third such deal this year and marks the first time a US-led consortium will re-enter Iraq’s oil industry in more than 30 years. It is a blow to Lukoil of Russia, which had signed an agreement to develop West Qurna under Saddam Hussein and had been lobbying intensely for the field in the past weeks.