The foreign ministers of Mali, Mauritania, Niger and Chad unexpectedly postponed joint talks in Brussels with the European Union on Wednesday, the EU’s top diplomat said, as the bloc struggles to stabilise the region after a series of coups. A European force, know as Takuba, was set up to help Mali and West African Sahel neighbours Burkina Faso and Niger tackle militants linked to the so-called Islamic State group and Al-Qaeda who have occupied swathes of territory where their borders meet. As Islamist militants grow in strength, local sentiment has hardened against European involvement. EU fo…