At a meeting of foreign ministers in Belgrade, US Secretary of State John Kerry warned on Thursday that it would take more than airstrikes to stop fighters with the so-called "Islamic State" (IS) and that Syrian or Arab ground forces would be necessary. If troops could be assembled, Kerry was confident that the jihadists could be defeated in "months."

"I think we know that without the ability to find some ground forces that are prepared to take on Daesh (IS), this will not be won completely from the air," Kerry said in Serbia at a meeting of the Organization for Security and Cooperation in Europe (OSCE).

Later asked if he meant Western soldiers, Kerry clarified that he was "talking about Syrian and Arab, as we have been consistently."

In October, the US announced it would change its policy with regards to putting American military on the ground in Syria by deploying about 50 special forces to assist US-backed moderate rebels in strategic matters.

Germany's Foreign Minister Frank-Walter Steinmeier was quick to say at the Belgrade summit that while he agrees that airstrikes "are certainly not enough," he was just as convinced "that there will be no European troops on the ground in Syria."

Meanwhile, UN Secretary-General Ban Ki-moon has said the world body was working to start talks between Syria's warring factions and begin a countrywide cease-fire in Syria in January.

Britain begins bombing Syria

Kerry's comments came just hours after the UK launched its first series of bombing raids on IS targets, joining the US and France in the campaign - three weeks after gunmen loyal to the terrorist group killed 130 people in Paris.

In the debate over whether or not to join the airstrikes, Prime Minister David Cameron said they would be assisting some 70,000 moderate opposition fighters in Syria ready to take on IS on the ground, although his opponents in parliament questioned this claim.

Kerry and his Russian counterpart, Sergei Lavrov, met on the sidelines of the OSCE meeting. The White House and the Kremlin remain at odds over the position of Syrian President Bashar al-Assad. Russian leader Vladimir Putin referred to his regime as the "legitimate government of Syria" in his annual state of the nation address on Thursday.

Kerry: Assad leaving could end conflict in months

The US top diplomat argued that a "political transition" to remove Assad from power in Syria would make it easier to create a broader international coalition - "the Syrian army together with the opposition...together with Russia, the United States and others to go and fight Daesh."

"Just imagine how quickly this scourge could be eliminated, in a matter of literally months, if we were able to secure that kind of political resolution," Kerry said.

At a NATO meeting in Brussels the day before, Kerry also called on the nations in the defensive alliance to intensify their role in the fight against IS. While many nations back the effort against IS, relatively few participate in the bombing campaign against the group.

es/jm (AFP, dpa, Reuters)