Islamic State crisis: Turkish-Syria border 'much tighter'

The BBC's Ian Pannell has visited the Turkish-Syrian border looking for evidence of the Turkish military build-up.

He also went to areas controlled by the so-called Islamic State group (IS) on the Syrian side of the border to see how things have changed there in recent weeks.

Turkey has been a reluctant partner in the US coalition against IS, but recently it has bombed IS and Kurdish positions.