David Cameron pledged to help America “destroy” self-styled Islamic State (IS) extremists in Syria as he gave his clearest signal yet that UK forces could be asked to join air strikes.

The discovery by Iraqi forensic teams “of mass graves believed to contain some of the soldiers killed by Islamic State (IS) militants last year” (Irish Examiner, 7 April), is, I fear, merely the first in a cycle of IS atrocities as it retreats.

US president Barack Obama has led worldwide condemnation of the killing of a Japanese journalist by Islamic State (IS) militants, calling it a "heinous murder".

US-led coalition air strikes on Syria have killed more than 500 people, mainly Islamic militants, since they began last month, activists said as fighting flared in the northern Syrian border town of Kobani.

US and coalition air strikes have forced some Islamic State militants out of the Syrian border town of Kobani, but it may yet fall under the extremists’ control because air power alone cannot prevent it, a Pentagon spokesman said.

The foreign ministers of Germany and Britain said they would not be taking part in air strikes in Syria against the Islamic State militant group.

President Barack Obama has moved to deepen the US military role in the volatile Middle East, vowing to wage an unrelenting counter-terrorism effort that will rely on air strikes to target Islamic State (IS) fighters in both Iraq and Syria.