U.S. President Barack Obama vowed to combat the Islamic State of Iraq and al-Sham (ISIS) killers of American journalist James Foley as the U.S. has begun surveillance flights in Syria for potential airstrikes on militia targets. "Our message to anyone who harms our people is simple: America does not forget, our reach is long, we are patient, justice will be done," Obama told veterans on Tuesday who had gathered at the American Legion's National Convention in North Carolina.He said, "We have proved time and time again we will do what's necessary to capture those who harm Americans," pointing to the approval of U.S. surveillance flights on ISIS units in Syria. Obama is considering extending, the air strikes against the militant group's fighters in Iraq and across the border into Syria, which has been embroiled in a three-year civil war.Freelance journalist James Foley was kidnapped in November 2012 in northern Syria and beheaded last week by ISIS. In the beheading video, the group warned the U.S that next it would kill another missing American journalist, Steven Sotloff, if U.S. airstrikes continue. "Rooting out a cancer like ISIS won't be easy, and it won't be quick," said Obama in his speech.ISIS captured a large part of eastern Syria and crossed into Iraq earlier this year. Turkmens in northern Iraq are the latest victims of the group. According to UNICEF officials, ISIS has massacred 700 Turkmen civilians in a northern Iraqi village and besieged Shiite Turkmen civilians in the town of Amirli in Salahuddin province. Nihat Bayatlı, an Amirli resident, told Ankara-based Anadolu Agency that 20,000 people are resisting the forces without electricity, water and food resources.