Iraq has tightened security and deployed extra troops around oil infrastructure and oilfields to help protect its vital energy industry from insurgents who have gained ground over the past week, a senior Iraqi security official said.

Brigadier Moussa Abdul-Hassan, chief of the South Oil Police, said additional troops have been deployed around oilfields, energy facilities, drilling locations and oil companies’ headquarters. Militants from Iraq and the Levant have routed Baghdad’s army and seized much of the north half of the country in the past week, threatening to break up Iraq and unleash all-out sectarian warfare.

“We have doubled security measures to keep oilfield operations and companies 100% safe. Now we have more than 100,000 oil policemen on ground on high alert, ready to protect energy facilities in the south,” Hassan told Reuters.

“We formed a crisis cell to closely monitor the security of foreign oil companies and we assured companies ... that their security is our top priority.”

Iraq looks to its massive oil resources for its future stability and prosperity, but still confronts a resilient Sunni Islamist insurgency now pushing southward towards Baghdad.

Iraq’s south, where the majority of the oilfields being developed by foreign firms are located, has been relatively safe and stable for the past two years.

“The checkpoints and protection posts were almost doubled and oil police members have been equipped with more powerful weapons, including rocket-propelled grenades and rifles,” Hassan said.

Basra, the main city in the far south at the edge of the Gulf, has enormous strategic importance as the hub for oil exports accounting for over 95% of government revenue.