BAGHDAD: The United States has bombed militants near Baghdad in support of Iraqi forces, striking close to the capital for the first time in its expanded campaign against Islamic State extremists.

The US airstrike against IS fighters in the Sadr al Yusufiyah area, 25km from Baghdad, came as world diplomats pledged to support Iraq in its fight against the militants and less than a week after US President Barack Obama ordered a ‘relentless’ war against IS.

‘US military forces continued to attack (IS) terrorists in Iraq, employing attack and fighter aircraft to conduct two airstrikes on Sunday and Monday in support of Iraqi security forces near Sinjar and southwest of Baghdad,’ the US Central Command said in a statement.

‘The airstrike southwest of Baghdad was the first strike taken as part of our expanded efforts beyond protecting our own people and humanitarian missions to hit [IS] targets as Iraqi forces go on offence, as outlined in the President’s speech last Wednesday.’

The strikes destroyed six IS vehicles near Sinjar and an IS position southwest of Baghdad that had been firing on Iraqi forces.

They bring the number of US airstrikes across Iraq to 162.

Iraqi security spokesman Lieutenant General Qassem Atta on Tuesday welcomed the expanded American action, saying the US ‘carried out an important strike against an enemy target in Sadr al Yusufiyah’.

Sadr al Yusufiyah lies in the Euphrates Valley, between the militant stronghold of Fallujah, west of Baghdad, and the key battleground of Jurf al Sakhr, further south. It is one of the closest front lines to Baghdad where Iraqi government forces and allied militia have struggled to defend their positions.

IS militants have seized a swathe of territory in Iraq and Syria, committing widespread atrocities.

The expansion of the US air campaign came as representatives from about 30 countries and international organisations, including the United States, Russia and China, vowed during talks in Paris on Monday to support Iraq in the fight against IS.

In a joint statement, diplomats promised to back Iraq ‘by any means necessary, including appropriate military assistance, in line with the needs expressed by the Iraqi authorities, in accordance with international law and without jeopardising civilian security’.

On the ground in Iraq, sporadic clashes broke out on Monday near the town of Dhuluiyah, north of Baghdad, where security forces and allied tribesmen prepared for an operation against IS-led militants.