Turkey threatens year’s delay to Swedish and Finnish entry to Nato

Issue may derail alliance summit as Ankara digs in on accusation that Nordic countries harbour terrorists

Turkey has said it is willing to delay Swedish and Finnish membership of Nato for more than a year unless it receives satisfactory assurances that the two Nordic countries are willing to address support for Kurdish groups it regards as terrorist organisations.

The issue threatens to derail a vital Nato summit due to start in Madrid on 29 June.