- 5 updates
President Barack Obama has approved sending up to 1,500 more troops to Iraq, roughly doubling the number of US forces on the ground.
The White House said it would also ask Congress for $1.6 billion for a new "Iraq Train and Equip Fund" and billions more for operations to battle IS.
Pentagon spokesman Rear Admiral John Kirby said the funds would need to be approved before the first additional forces head to Iraq, which could happen within weeks.
Kirby added: "(Iraqi forces are) going on the offence now. And what this is designed to do is to help them continue to be able to do that, to improve their capability and their competence on the battlefield."
He stressed no American troops would take on combat roles.
Around 1,400 US troops are currently on the ground but the new authorisation gives allows the US military to deploy up to 3,100.
Defence Secretary Michael Fallon has met with Iraq defence secretary Khaled al-Obeidi to discuss what Britain can do to assist the fight against IS.
Defence Secretary Michael Fallon said Britain is "stepping up" its military presence in Iraq, after announcing the deployment of extra military advisers to help train forces in the fight against Islamic State.
"We are going to be stepping up our training effort," Mr Fallon told the BBC.
"I can't give you precise numbers. I'm here to evaluate training needs and there are areas of expertise, particularly in counter-IED, roadside car bombs, where we can help from our experience in Afghanistan.
"So we will be putting in more training people to help at the training centres across the country, not just in the Kurdish areas."
The UK will send more military personnel to Iraq to help train forces to fight Islamic State, Defence Secretary Michael Fallon has confirmed.
Mr Fallon said advisers will be placed in training centres across the country, as he announced an expansion of UK involvement after a small team was sent to the northern city of Erbil last month.
Forces will offer further training to Iraqi soldiers and Kurdish Peshmerga fighters, including skills such as sharp-shooting and first aid.
But the Ministry of Defence insisted the move would not lead to the deployment of combat troops.
“It is right that we do more to help Iraqi forces take the fight to ISIL on the ground which is why the UK is offering the further training, support and assistance," Mr Fallon said.
British soldiers could return to Baghdad to support Iraqi security forces in their fight against Islamic State.
A number of officers are expected to be sent to join the US-led training mission to the Iraqi capital.
"We are exploring what more can be done on training as part of a future package of support aimed at bolstering the ability [of the Iraqi military] to tackle [Islamic State]," a senior defence source told The Times.
The Ministry of Defence is due to make an announcement later.