THE US military jumped into action today after President Barack Obama gave the go-ahead for airstrikes against Islamic State (Isis) fighters in Iraq.

Two Hornet fighter aircraft dropped 500lb laser-guided bombs on a mobile artillery piece that had been shelling Erbil, the capital of the autonomous Kurdish region.

It was the first effort by US air forces to back the Kurdish peshmerga fighters and Iraqi government troops in their struggling opposition to the Isis forces which have seen dramatic advances in recent days.

The Kurdish peshmerga, who are short of ammunition and stretched thin along a huge front of over 700 miles, have been forced to retreat in the face of Isis assaults and peshmerga fighters near Erbil itself are now under fire.

President Barack Obama had authorised the strikes on Iraq on Thursday, saying they were to protect religious minorities and prevent “genocide.”

The military strike was not the first action under President Obama’s instructions.

Many thousands of residents from the Yezidi religious sect had fled from the Iraqi town of Sinjar after Isis fighters overwhelmed Kurdish forces.

A huge number, including many women, children and elderly people, were trapped in hiding on Mount Sinjar without food or water and were at risk of starvation.

On Thursday evening, the US dropped thousands of gallons of drinking water and 8,000 packaged meals to the Yezidis and President Obama said there would be further humanitarian drops if necessary.

But there was little humanity in the airstrike that followed near Erbil.

President Obama has accused Isis of attempting “the systematic destruction of the entire people, which would constitute genocide.”

But the President, who opposed the 2003 invasion, has claimed there would be no return of ground troops to Iraq. The last US troops left in 2011.

Mr Obama was at pains to assure US citizens that he was not about to get “dragged into fighting another war.”

But Isis has enjoyed a spectacular run of military successes in Iraq and it may be that the US will see the need to back its fragmented puppet government with more than occasional air strikes.