The high-level COBRA meeting to be held at Downing Street today is expected to centre around stepping up the UK government's response.
"The PM is now back in the UK and will chair the routine daily COBRA at 1300 hrs for latest updates on situation in Iraq," announced a tweet from Cameron's official Twitter account.
The Prime Minister's decision to return home a day earlier than expected followed criticism from some of his own party MPs for allowing himself to be photographed on a Portuguese beach while Royal Air Force (RAF) crews were flying dangerous missions to drop humanitarian supplies to Yazidi refugees trapped on Mount Sinjar.
RAF Tornado jets prepare to carry out surveillance operations to support aid deliveries, with UK Chinook helicopters expected to arrive in Cyprus later.
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The UN has warned that tens of thousands of civilians are trapped on mountains in northern Iraq near the Syrian border by fighters from militant group Islamic State (ISIS).
US forces have carried out a number of air strikes targeting ISIS forces near Irbil, the capital of Iraqi Kurdistan, while drones have also fired on jihadist fighters.
America has also sent 130 more military advisers to the Kurdish region of northern Iraq.
The UK's shadow foreign secretary has urged the UK to step up its response.
Labour's Douglas Alexander said, "Clearly the UK must now also be doing all that we can to assist the vital humanitarian effort that is under way to help save lives and prevent further suffering."
"Our task is to make our contribution and support the work required to save lives and secure the safety of these vulnerable people," he said.