Senior officials from 21 countries are gathering in London to discuss efforts to tackle the jihadist militant group, Islamic State (IS), in Syria and Iraq, BBC News reports.

Those taking part in the one-day conference include U.S. Secretary of State John Kerry and Iraqi Prime Minister Haider al-Abadi.

They will discuss how to halt the flow of recruits and money to IS. They will also look at providing more military help to those fighting on the ground, and boosting humanitarian aid.

BBC diplomatic correspondent James Robbins says ministers will be exploring ways to accelerate and intensify a long-term campaign. Recent attacks by Islamist militants in France have put even greater political pressure on governments to show decisive results, he adds.

Kerry, who will co-host the talks with UK Foreign Secretary Philip Hammond, said there was "greater determination" than ever to defeat IS. "Terrorists want to drive us apart, but in fact their actions have had the opposite effect - they're bringing us together," he told reporters before leaving for London.

He had been holding talks in Washington with EU foreign policy chief Federica Mogherini. Mogherini said the conflict was "not a fight between the West and Islam". The anti-IS coalition, she added, was "a partnership that unites us all against a phenomenon that is brutally devastating societies all over starting with the Arab countries".

IS controls large areas of Iraq and Syria, in which it announced the creation of a "caliphate" in June.

Speaking in Iraq before leaving for London, Abadi praised the U.S.-led coalition's air campaign against IS, but said the international community needed to do more to train and equip ground forces.

The countries taking part in Thursday, Jan 22 conference along with the U.S. and UK are Australia, Bahrain, Belgium, Canada, Denmark, Egypt, France, Germany, Iraq, Italy, Jordan, Kuwait, the Netherlands, Norway, Qatar, Saudi Arabia, Spain, Turkey and the United Arab Emirates.

The U.S.-led coalition has carried out more than 1,000 air strikes since its campaign against IS began in Iraq in August and in Syria in September.

The U.S. says the campaign has been successful but that is likely to stretch on for years.