01:25 - Source: CNN
ISIS launches assault on Baiji Oil Refinery

Story highlights

ISIS says it controls several buildings at the Baiji oil refinery

Iraqi government security officials say Iraqi forces remain in full control

The refinery, Iraq's largest, has long been a lucrative target for militants

Irbil, Iraq CNN  — 

ISIS claimed it controlled part of Iraq’s largest oil refinery Sunday, posting images online that purported to show the storming of the facility, fierce clashes and plumes of smoke rising above the contested site.

The group said it launched an assault on the Baiji oil refinery late Saturday. By Sunday, ISIS said its fighters were inside the refinery and controlled several buildings, but Iraqi government security officials denied that claim and insisted Iraqi forces remain in full control.

CNN couldn’t independently verify ISIS’ claim. It wouldn’t be the first time that militants and Iraqi forces have battled over the refinery, a key strategic resource that has long been a lucrative target because the facility refines much of the fuel used by Iraqis domestically.

If an attack damaged oil fields or machinery, it could have a significant impact.

The refinery is 40 kilometers (25 miles) from Tikrit.

CNN’s Jennifer Deaton and Catherine E. Shoichet contributed to this report.