ISTANBUL — Kurdish militants demanded concrete steps from Turkish authorities to advance a peace process on Tuesday, warning that otherwise its future was at risk. “Our movement is at a stage of serious and critical thinking and of taking new decisions,” the KCK, a political umbrella group linked to the Kurdistan Workers Party (PKK) militants, said in a statement published on a website close to the organization. “Concrete steps should be taken by the (ruling) AK Party. Otherwise the peace process is at a very critical and dangerous stage, and near ending.” The Turkish government launched talks with PKK leader Abdullah Ocalan, who is in jail on an island near Istanbul, in 2012, in a bid to end a three-decade armed struggle that has killed 40,000 people and stunted the development of the mainly Kurdish southeast. The PKK, which is designated a terrorist group by Turkey, the United States and the European Union, subsequently declared a ceasefire and began withdrawing from Turkey to camps in northern Iraq where its fighters are based. Failure to strike a deal could be a thorn in the side of President Tayyip Erdogan, who needs the AK Party which he founded to secure a large majority in a national election in June to push through plans for an executive presidency. He has invested considerable political capital in the peace talks despite fierce nationalist opposition. — Reuters