MARIAM BEK, Iraq (AP) — As Islamic extremists seek to sweep away borders in their advance across the Middle East, Kurds in northern Iraq appear to be in the process of digging a new one, asserting their claim to hotly disputed territory and expanding their semi-autonomous region in a bid for greater autonomy or outright independence.

The emerging frontier of sand berms, trenches and roadblocks is being built to take in areas Kurdish fighters seized as Sunni militants led by the Islamic State of Iraq and the Levant swept across northern Iraq last month, routing the armed forces of the Shiite-led government in Baghdad and raising fears the country could be torn in three.