UK military action: Your views
David Cameron has said the UK is ready to "play its part" in fighting Islamic State, which he called an "evil against which the whole world must unite".
Speaking at the UN in New York, the prime minister said the Iraqi government had made a "clear request" for international military assistance against IS, which has taken control of large parts of Iraq and Syria in recent months.
In his UN speech Mr Cameron also said "past mistakes" must not be an "excuse" for inaction, but is the UK as a nation ready to go to war again?
BBC News website readers have been sending in their thoughts.
Colin Howard, Wimborne, Dorset, UK
This government seems to think RAF personnel risking their lives is not important as long as there are no boots on the ground.
They are it seems disposable, but vital in enabling MPs carry out their own wishes.
We may lose a family member in yet another pointless political war but what do Cameron or the MPs care?
Perhaps they should go out there if they are so concerned.
Vincent Waddelove, UK
I support limited military action. These jihadists are killing civilians in huge numbers, we have stood by for quite long enough.
Jack Sherlock, Surrey, UK
Although I believe action needs to be taken, given our current financial situation, and the forced imposition of fiscal measures to reduce the country's deficit on the general population, where is the finance coming from to pay for this action?
Hadi Aziz, UK
Attacking IS is one of the way to stop them, and it is essential that the UK takes part in this justified war. But the most important thing is to put pressure on Turkey to stop supporting IS.
John, Preston, UK
Watching Cameron explaining how this latest addition of IS to the bogeyman list of Al Qaeda, Osama Bin Laden, Saddam Hussein, and weapons of mass destruction, are a direct threat to the safety of residents in Great Britain, made me feel ill.
This seems to me nothing more than another excuse to drag the UK into supporting the US in a formulated plot to control their interests.
Matthew Lockyer, Australia
The (un)Islamic State is a lethal threat to the everyone in the vicinity of its so called caliphate. It is a a very serious threat to the nations of the middle east.
It is a threat to all the men women and even children of all western nations and especially to those in United Kingdom. Those in the whole region needs our help.
Nigel Carpenter, Norwich, UK
I am totally against any more fighting in the region.
America only has oil as its aim. There are other disasters in the world America could help with in a positive way but if they have no oil, they ignore them.
We (Britain) along with America created the total chaos in Iraq we now see - so we should not spend more money just killing people in a hope it will all go away.
Spend the money on getting everyone concerned around a table and talk peace for the world - that is the only way the world will ever be safe.
Jackie Johnson, Shrewsbury, UK
There is no "reasoning" with the thugs in Islamic State. They will not make peace as long as they view anyone who does not believe what they believe as worthy of death in its most barbaric form.
I think Cameron is right when he says the only thing they will respect is force.
Robert Reynolds, UK
All who wish for themselves and others to live in civilisation, will wish to see action to remove threats from ISIS; against citizens, against states with some measure of electoral discretion and against global trade with a basis of at least functional legitimacy.
Certainly, our shared future depends on our shared interventions, but also on address of causes.
The inroads of insurgency in Iraq are owed precisely to that country's lack of democracy, an atomised people sheltering under religious and tribal flags, unable to muster strength in its own defence.
Let us intervene - belatedly, now, with all haste possible.
Frazer Broomby, UK
This is a potential disaster with potentially huge cost implications both human and financial. It will cost an already bankrupt country, with massive and increasing debts and a tangle of serious home issues, even more, yet we seem to think we can afford it and think we have an important role to play in this regional issue.