Islamic State militants will not be defeated "overnight", the Foreign Secretary has warned.
Philip Hammond also told ITV News Washington Correspondent Robert Moore that the Government could yet bring another parliamentary vote on deploying British air power over Syria.
It is "deluded" to think ignoring the "barbarism" of Islamic State (IS) will somehow diffuse the threat of the anti-Shia jihadists, the Foreign Secretary told Good Morning Britain.
Philip Hammond said IS were already prepared to carry out atrocities all over the world, so it was unlikely airstrikes would exacerbate the situation.
The Government has not ruled out military action in Syria to tackle Islamic State militants, the foreign secretary said.
When asked whether British air strikes in Iraq - which look set to be approved tomorrow - could be extended to Syria, Philip Hammond said: "We haven't ruled out anything for the future. We will have to see how the struggle against Isil goes.
"But the important thing... is that if we were to decide at some point into the future that it would be right to conduct airstrikes in Syria then we would come back to the House of Commons, there would be another debate - all the issues around that would be fully discussed and a decision made at that time."
Mr Hammond also ruled out deploying British ground troops, he said: "There will be a ground operation - it's just that we will not be providing ground combat troops
"We are very clear about that. Not only because we don't think, frankly, public opinion would support such involvement. But also we don't think such an involvement would be helpful."
Foreign Secretary Philip Hammond has said he expects the response to Islamic State to be a "long struggle against a poisonous ideology".
He said the military dimension of the conflict was just one part of the counter-attack, which he said is also financial and ideological.
ITV News' International Affairs Editor Rageh Omaar began by asking him whether Parliament would be consulted in advance of any military action:
Foreign Secretary Philip Hammond has said that western powers will push ahead with further sanctions against Russia over the conflict with Ukraine.
He told the BBC that the sanctions could be lifted at a later stage if a proposed ceasefire sticks.
The Government would consider sending British forces to Iraq in a training capacity but not for combat roles, Foreign Secretary Philip Hammond has told ITV News.
He said he believed Iraqi forces lacked "technical support, surveillance, intelligence, air cover and in some cases weapons and ammunition" rather than manpower.
Foreign Secretary Philip Hammond has told ITV News British agencies are "urgently investigating" a video that appears to show a British jihadist killing a US journalist.
He said the first step is to authenticate the video and then to establish the identity of the "murderer".
ITV News joined a Kurdish unit fighting Islamist militants near Irbil and found them using tanks from the 1950s and short on ammunition.Read the full story ›
Foreign Secretary Philip Hammond has said that the UK is taking a lead in preparing an EU resolution that will condemn ISIL, seek to freeze asset flows and take steps against individual terrorist and their facilitators.
He said EU member states were committed to "pushing back against the threat from ISIL - a threat to civilization, a threat to the region and a threat to us here in Europe."
Foreign Secretary Philip Hammond will chair a meeting of the COBR emergency committee this afternoon, Downing Street has announced.
The Foreign Secretary will chair a COBR meeting this afternoon on the situation in Iraq.