The UK will not be "dragged into a war in Iraq", ministers insisted as the Government defended its decision to move beyond simply providing humanitarian aid.
David Cameron said the Government has a "fully worked through" strategy to tackle Islamic State (IS) extremists and argued that limited action was needed to prevent violence spreading to British streets.
The Prime Minister said the UK was ready to provide arms to Kurdish fighters who were the "first line of defence" against the "murderous extremists" of IS in northern Iraq.
Mr Cameron, who cut short a break in Portugal earlier this month to respond to the emergency, is expected to head to Cornwall for another holiday this week but insisted he will be able to manage the Government's response to the crisis from there.
"Wherever I am, wherever I am in the world I am always within a few feet of a BlackBerry and an ability to manage things should they need to be managed," he said.
He maintained his resistance to recalling Parliament to debate the crisis, saying it was unnecessary as "we are not contemplating things that would require that".
With the US carrying out air strikes against IS forces, Defence Secretary Michael Fallon revealed at the weekend that the RAF had now deployed the Rivet Joint surveillance aircraft alongside Tornado jets to provide vital intelligence on extremist movements across Iraq.
But Foreign Secretary Philip Hammond, who chaired the latest meeting of the Government's Cobra committee, sought to allay fears about mission creep by stressing there were no plans for combat troops to return to Iraq.
He said: " The priority is the humanitarian situation. There are huge numbers of displaced persons, there are persistent stories of atrocities being committed against people who are fleeing from the violence that's going on, that has to be our number one priority.
"But we are also clear that we face a shared threat with the Iraqi people from IS and its particularly despicable brand of hate preaching.
"We have to rise to that challenge; we have to deal with it. We will, if requested, provide support to the Iraqi government.
"The Prime Minister has been very clear that this is not about being dragged into a war in Iraq, we will not be putting combat boots on the ground."
Labour and senior Church of England bishops have complained that the Government has no "coherent or comprehensive approach" to Islamist extremism and is failing to protect Christians from persecution.
But Mr Cameron told BBC Breakfast: "We do want to have, and we do have, a fully worked through strategy for helping allies to deal with this monstrous organisation, IS.
"So we are helping the Kurds, we are working with the Iraqi government to make sure it is more representative of the whole country and, of course, we are working with neighbours and allies to put the maximum amount of pressure on IS and make sure it is properly dealt with.
"We have said that if the Kurds, the Peshmerga, want to have arms from us, that is something we would consider favourably.
"Up to now they have not been making that request. Really the sort of weapons they have been using have been more eastern bloc variety, and so they have been supplied by others."
He warned that IS had already started inflicting "damage here in Europe", highlighting a shooting at a Jewish museum in Brussels.
"We have already had the first IS motivated attacks in Europe; for instance, the dreadful terrorism that took place in Brussels just a few weeks ago."
However, he stressed: "I want to be absolutely clear to you and to families watching at home, Britain is not going to get involved in another war in Iraq.
"We are not going to be putting boots on the ground. We are not going to be sending in the British Army.
"Yes, we should use all the assets that we have, our diplomacy, our political relationships, our aid, the military prowess, the expertise that we have to help others - we should use these things as part of a strategy to put pressure on Islamic State and make sure this terrorist organisation is properly addressed and it cannot cause mayhem on our own streets."
Mr Cameron said "keeping people safe here at home" was his "number one, two and three priorities".
But Mr Cameron came under further pressure from a prominent Anglican, as Canon Andrew White from Baghdad's St George's Church called on the Government to offer asylum to up to 30,000 Iraqi Christians.
He told BBC Radio 4's Today programme: "Christianity (in Iraq) could well be nearly dead and Britain has refused asylum to any Iraqi and now we are desperate. It's a matter of life and death."
Downing Street said applications for asylum from refugees would be considered on a case-by-case basis.
"We have a proud tradition in this country of offering sanctuary to those fleeing persecution if they need it," a No 10 spokeswoman said.
"Each case would be assessed on its individual merits."
Defence Select Committee chairman Rory Stewart, a former coalition deputy governor in Iraq following the 2003 war, told Today: " I have certainly been a supporter myself personally of the idea that we should be providing some asylum to people from Syria, I think we may have some obligation towards Iraq.
"But I would have thought that the Prime Minister, in looking at this, would be looking at getting an international engagement with different countries sharing the burdens."
He backed arming the Kurds, but warned that their fighting forces needed significant reforms and added: " It is not just a humanitarian thing any more. Arming the Kurds is taking a military position against the Islamic State. But before we do any of this we need far, far more information.
"The lesson, above all, of our last intervention in Iraq is we have got to focus on what we can do."
Downing Street said the Kurdistan government has insisted it is capable of "fighting this battle" and has not requested combat support.
In a statement following a meeting of the emergency Cobra committee, a No 10 spokesman said: " We remain open to supplying equipment directly and work is under way to identify what we could usefully provide. The UK is working hard with allies to make the most of our diplomatic, political, aid and military expertise, however as the Prime Minister made clear this morning, this is not about getting dragged into a war in Iraq, we will not be putting combat forces on the ground.
"Further, the Kurdistan Regional Government has not requested our assistance with putting combat forces on the ground, they say they are capable of fighting this battle, what they need is equipment which is why we will look at providing weapons to the Kurdish troops."
Mr Cameron has talked by telephone to the Emir of Qatar, the King of Saudi Arabia and the King of Jordan to discuss the Iraq and Gaza, Downing Street said.
A spokesman said: "The Prime Minister spoke to King Abdullah of Saudi Arabia this afternoon.
"On Iraq, the Prime Minister thanked His Majesty for the significant donation made by Saudi Arabia to the UN appeal and both leaders agreed on the importance of the international community coming together to help Iraq tackle the threat posed by these Islamic terrorists who are perverting the Islamic faith as a way of justifying their barbaric ideology.
"They both expressed support for Prime Minister designate Dr Al Abadi's efforts to form a unity government.
"The Prime Minister and His Majesty agreed that the world must come together to defeat ISIL terrorists. On Gaza, they agreed on the need to maintain the current ceasefire."