United States investigators say it is doubtful the Islamic State militant group is directly involved in a failed attack on a Texas cartoon exhibit of the Prophet Mohammed in which two gunmen were killed. IS said on its official online radio station that two soldiers of the caliphate carried out the attack on Sunday in the Dallas suburb of Garland.

US officials said while the claim of responsibility for the attack is being examined, investigators does not know whether the attack was launched under instructions from IS or whether the group is opportunistically claiming credit when it has little or no direct or indirect involvement. White House spokesman Josh Earnest said it is too early to say whether this attack means IS has come to the US.