The U.S., joined by European countries, has been hitting targets in Iraq since August.
Members of the influential Shammar tribe, one of the largest in northwestern Iraq, joined the Kurds in the fighting, a tribal figure said.
The Islamic State group reportedly executed at least two of its own members after accusing at least one of them of working for the CIA.
As ISIS seizes land in Iraq and Syria, the National Security Council briefed the president on strategy to combat the extremists
Militants surrounded a Turkish sovereign enclave in Syria and threatened to seize Kobane on the Syria-Turkey border.
With Obama predicting that airstrikes in Syria and Iraq could take years, defense companies are already cashing in.
U.S. oil prices slid the most in 17 months on Tuesday, with international oil prices close behind.
The U.K.'s Ministry of Defense confirmed the airstrikes were successful.
The Algerian government has the identities of Hervé Gourdel's killers two weeks after he was beheaded by an Islamist group.
The Islamic State group used to make millions a day from oil, but after U.S. and allied planes bombed refineries, that money is gone.
In the new video, Cantlie mocks the American strategy of employing air power combined with local ground forces in Iraq and Syria.
After more than six months of uncertainty, Afghanistan will allow U.S. forces to stay past December 2014, but safety fears remain.
Indian Prime Minister Narendra Modi is in the United States for five days.
Most Americans said they felt the U.S. would eventually use ground troops against ISIS in Syria or Iraq.
The Islamic State is a little more than a mile away from Baghdad, calling the effectiveness of U.S.-led airstrikes in Iraq into question.
Syria's army also carried out air raids in Aleppo province overnight, as well as in Hama in western Syria.
President Obama told "60 Minutes" he put too much trust into the Iraqi army.
In a speech at the World Economic Forum Sunday, President Erdogan said Turkey is prepared to join the fight against ISIS.
Destroying the makeshift refineries has led to a sharp increase in the price of diesel.
Experts say battle-hardened Chechen fighters joining the Islamic State pose a serious threat.
Oklahoma beheading suspect Alton Nolen is charged with attacking and killing Colleen Hufford, 54, Thursday.
U.K. Parliament has yet to OK similar action in Syria.