BBC News reports President Obama has hailed the support of Arab nations in air strikes on Islamic State (IS) militants, saying: "This is not America's fight alone." He was speaking hours after the U.S. and Arab allies launched their first air strikes against IS in Syria. Activists say at least 70 IS militants and 50 other al-Qaeda-linked fighters were killed in the strikes. Syrian officials say they were given advance warning of the strikes, but the U.S. state department has denied this. President Obama confirmed Saudi Arabia, the United Arab Emirates, Jordan, Bahrain and Qatar had taken part in or supported the strikes. He said the U.S. was "proud to stand shoulder to shoulder with these nations". The Pentagon said warplanes, drones and Tomahawk cruise missiles were used in the strikes.