The US government has offered $20million in rewards for information which leads to the whereabouts of four people it claims are top leaders of Isis.
The State Department claims each of the men has a high-ranking role within the militant group and has offered rewards worth millions of dollars for each individual.
The department announced it was offering up to $7m for Abd al-Rahman Mustafa al-Qaduli, who it has described as a senior Isis official who originally joined al-Qaeda’s affiliate in Iraq.
It is also offering up to $5m each for Abu Mohammed al-Adnani and Tarkhan Tayumurazovich Batirashvili, as well as up to $3 million for Tariq Bin-al-Tahar Bin al Falih al-‘Awni al-Harzi.
The department has described Adnani as an official spokesman for Isis, while Batirashvili, also known as Omar the Chechen, is said to be a battlefield commander in northern Syria.
Harzi is described as the group’s leader for the border region between Syria and Turkey.
Each of the men have been placed on a list of suspects sought through the Rewards for Justice programme.
The rewards were offered as Isis (also known as Islamic State) claimed responsibility for the attack on a Texas cartoon contest featuring images of the Prophet Mohamed.
The group said on its official online radio station that ‘two soldiers of the caliphate’ carried out the attack on Sunday in Garland.
Doubts have been raised over the claims however as counterterrorism experts accused the militant group of claiming involvement in attacks in which it did not have an operational role.
Federal officers have identified the two gunmen who opened fire on the exhibition organised by the anti-Muslim American Freedom Defense Initiative (AFDI) before they were shot dead by police, as Elton Simpson and Nadir Soofi, two Americans who lived in Phoenix.
Simpson’s social media had been scrutinised recently by federal authorities, although there had been no indication he was planning an attack, a federal official has told Reuters.
Isis has recently urged those in the US, Europe and Australia to carry out jihad in the countries where they live if they are unable to travel safely to Syria and Iraq.
The US-led military meanwhile has said it has launched 12 air strikes in Iraq and one in Syria against Isis militants since 4 May.