Fighters from the Islamic State group tightened their siege of a town on Syria's border with Turkey on Friday despite U.S.-led airstrikes aimed at defeating the militants in both Syria and Iraq, in a coalition that has now drawn widespread European support.
Britain, Washington's closest ally in the wars of the last decade, joined an alliance after weeks of weighing its options. Britain's parliament voted 542-43 to back Prime Minister David Cameron's decision to take part in airstrikes in Iraq.
Belgium's parliament also voted 114-2 to take part and Denmark said it would send planes. Six Belgian F-16s took off for a staging post in Greece even before the vote.