A report from the US Army Corps of Engineers has warned that the Mosul Dam in Iraq is at a ‘higher risk’ of failure than it was a year ago, with "an unprecedented level of untreated voids" in the dam’s foundation.

The report says the dam is at greater risk, largely due to the fact that no grouting took place in the structure when it was captured in 2014 for several weeks by Islamic State. It says new signs of distress were found in the 113m high structure.

No timeline for failure was suggested in the report, and Iraq’s Water Resources Ministry says there is no imminent danger of collapse, but the report stresses that work is urgently needed to help prevent a catastrophic failure.

Work is expected to begin soon on shoring up the dam, although critics have warned this is not a permanent solution to the problem.