Iraq crisis: Obama says US 'broke Mt Sinjar siege'
Mr Obama said the situation on Mount Sinjar had greatly improved.
Many of those displaced had now left the mountain and further rescue operations were not envisaged, he said.
However, Mr Obama said the US would continue carrying out air strikes against Islamic State (IS) militants.
Iraqi and Kurdish forces who were fighting the militants would also continue to receive US military assistance, Mr Obama said.
'Modestly hopeful'
The president re-emphasised the need for Iraqis to find a political solution to the crisis, describing the prospect of a new and inclusive government, led by Haider al-Abadi, as an "enormous opportunity".
"He still has a challenging task in putting a government together, but we are modestly hopeful that the... situation is moving in the right direction," Mr Obama said.
Mr Abadi, a deputy speaker of parliament, has been asked by the Iraqi president to form a new government. However, the current Prime Minister, Nouri Maliki, whose coalition won the most seats in April's election, has vowed to contest the move in court.
Mr Maliki said the move violated the constitution.
Iraq's military response to a rapid advance by IS has been hampered by political chaos in Baghdad.
On 29 June, the militant group said it had created a caliphate, or Islamic state, stretching from Aleppo in Syria to the province of Diyala in Iraq.
The United Nations estimates that 1.2 million Iraqis have been internally displaced in the last few months.
It has declared Iraq a "Level 3 Emergency", its highest ranking of a crisis. The move should enable more resources to be directed in support of humanitarian efforts.
The UN had earlier estimated that tens of thousands of people, most from the Christian and Yazidi religious minorities, were besieged on the mountain after being forced to flee their homes.
But US forces sent to Mt Sinjar found fewer people than expected - partly because thousands had left the mountain each night over the past days.
BBC
