US Secretary of State John Kerry has spoken in Paris of the fight against IS and how it is a "battle between civilisation itself and barbarism".
Mr Kerry said it is an "assault on our collective sense of reason and purpose and an attack on civility itself."
Don't mistake what these attacks represent. This is not a clash of civilisations. These terrorists have declared war against all civilisations. They killed Yazidis because they are Yazidis. They kill Christians because they are Christians. They kill Shia because they are Shia.
They rape and torture and pillage and call it the will of God.
They are in fact psychopathic monsters and there is nothing civilised about them. This is not a case of one civilisation pitted against another. This is a battle between civilisation itself and barbarism.
John Kerry has arrived back in the United States after breaking his leg in a cycling accident.
The US Secretary of State landed at an airport in Boston on Monday evening before heading to Massachusetts General Hospital for further treatment.
Mr Kerry, who is 71, broke his right femur while cycling in south-eastern France on Sunday and spent a night in a Geneva hospital.
He tweeted: "Headed back to Boston. Look fwd to getting leg set & getting back to @StateDept! Meantime, work goes on. Big thanks for well-wishes."
Kerry was due to attend a meeting of international ministers in Paris today to discuss the fight against Islamic State.
Earlier it was confirmed that Kerry would participate by telephone in the summit.
John Kerry, the US Secretary of State, has broken his leg in a cycling accident in France.
Kerry broke his right femur after reportedly hitting a curb while cycling in Scionzer, south-eastern France on Sunday.
The 71-year-old was taken by helicopter from the scene and transferred to a hospital in Geneva, where it was decided he would remain overnight for further observation.
He has cancelled visits to Spain and France, where he was due to attend a conference to discuss the battle against Islamic State.
Kerry was in "great spirits" despite the accident, State Department spokesman John Kirby said, adding that the Secretary of State was expected to make a full recovery.
US Secretary of State John Kerry will meet Russian President Vladimir Putin in Sochi on Tuesday for talks on Ukraine, Syria and Iran.
Mr Kerry's trip to Russia - his first since 2013 - is aimed at maintaining "direct lines of communication" with the Kremlin and to "ensure US views are clearly conveyed", the US State Department said.
The visit comes amid a period of heightened tension between the US and Russia over the latter's actions in the Ukraine conflict.
A diplomatic source was quoted by Russian media as saying that Kerry's visit "is very symbolic".
The US Secretary of State John Kerry has cancelled plans to return to the USA to continue Iran nuclear talks in Switzerland amid signs of troubled negotiations.
He was due to return to the USA to attend an event honoring his late colleague Edward Kennedy, the dedication of the Kennedy Institute in Boston with the late senator's family.
But the State department said that "given the ongoing nuclear negotiations in Switzerland, the secretary regrets he will not be able to share this special time with them in person."
His decision to stay comes as the talks appear to have hit obstacles ahead of a March 31 target for the outline of a final deal to be negotiated by the end of June.
US Secretary of State John Kerry has said America will "in the end" have to negotiate with Syria's President Assad, according to CBS News.
Kerry said the US is willing to negotiate within the context of the Geneva process, which calls for negotiated political transition in Syria.
America and "other countries" are exploring ways to reignite the diplomatic process in Syria, he added.
But Kerry admitted that getting Assad to negotiate may require increased pressure on him.
Secretary of State John Kerry said the US had no intelligence on who was behind the shooting of Russian opposition politician Boris Nemtsov.
"The bottom line is we hope there will be a thorough, transparent, real investigation, not just of who actually fired the shots, but who, if anyone, may have ordered or instructed this or been behind this," he told ABC News' This Week.
US Secretary of State John Kerry has said that he and his European counterparts are agreed that the conflict in eastern Ukraine "will not end through military force".
He emphasised that there was "no split" between US and European policy towards Ukraine.
"We will stand together in support of Ukraine and in defence of the common understanding that international borders ... cannot be changed by force in Europe or anywhere else." Mr Kerry added.
John Kerry says that the largest threat to Ukraine is Russian aggression but that the west is not seeking conflict with Russia.
The Secretary of State says the US is seeking a diplomatic solution to the conflict in Ukraine but is not prepared to "close our eyes" to Russian tanks and fighters crossing the border.
Speaking after talks in Kiev with Ukrainian President Petro Poroshenko, Kerry demanded an immediate commitment by Moscow to a ceasefire in eastern Ukraine that was backed up by actions on the ground.
Russia has consistently rejected accusations from Kiev and the West that it supports a pro-Russian rebellion in eastern Ukraine with troops and heavy weaponry.
The US has pledged $16.4 million in humanitarian aid to help civilians in eastern Ukraine.
Secretary of State John Kerry arrived in Kiev this morning for talks with the embattled Ukrainian leadership.