Oil prices soared Thursday on escalating violence in Iraq, as government troops recaptured a major refinery and the U.S. said it was sending in military advisers to train Iraqi forces.

Brent crude for August delivery rallied 80 cents in London to $115.06, its highest since early September.

In New York, West Texas Intermediate for July delivery added 46 cents at $106.43 a barrel.

The rise in prices continued after President Barack Obama announced that he was ready to send 300 military advisers to Iraq and if necessary to take "targeted" and "precise" military action to counter radical Sunni fighters.

"We will help Iraqis as they take the fight to terrorists who threaten the Iraqi people, the region and American interests as well," he said.

The extremists have captured swathes of the country's north but have yet to directly threaten the key oil-producing region in the south.

Iraqi forces regained full control on Thursday of the country's largest oil refinery after heavy fighting, officials said.

"The security forces are in full control of the Baiji refinery," Lieutenant General Qassem Atta, Prime Minister Nuri al-Maliki's security spokesman, said in televised remarks.

The crisis has rocked the global oil market because Iraq is the second-biggest producer within the 12-nation Organization of Petroleum Exporting Countries.

The country has more than 11 percent of the world's proven resources and produces 3.4 million barrels a day.