US Defence Secretary Ashton Carter on Tuesday visited the Turkish air base near Syria that has become a key hub for American-led air raids against Islamic State jihadists.

Turkey earlier this year allowed US forces to use the Incirlik base outside the southern city of Adana for bombing raids against IS targets in Syria. The Turkish air force later also joined the campaign.

"The goal of the visit is to meet with US soldiers in order to thank them for their contribution to the ongoing air campaign‎ against ISIL," said a US diplomatic source, using an alternative acronym for IS.

Gaining the use of Incirlik, which lies just 160 kilometres (100 miles) from the Syrian border, was a huge boost to the US campaign against IS, which had relied on air bases at a far greater distance.

The US source said Incirlik had now become a "major allied hub of activity".

"Together over the past month, we have achieved the highest operational tempo against ISIL since the start of the air campaign in August 2014," said the source.

President Barack Obama on Monday said the US and its allies were hitting IS "harder than ever" and warned the extremists' leaders: "You are next."
Source: AFP