Barack Obama has asked world leaders to do more to open their hearts to refugees fleeing conflict in the Middle East.

Speaking to the United Nations General Assembly in New York, the US president claimed the world enjoys stronger stability when help is offered to people in desperate need.

He added the ongoing violence in the region "will not be quickly reversed" and the US and other world powers have limited powers to bring about lasting peace.

Image: The US president said diplomacy was key to resolving Syria's civil war

Emphasising that the solution to Syria's civil war is diplomatic rather than military, Mr Obama warned outside intervention in the country's civil war and other conflicts in nations fractured along ethnic and tribal lines would be unlikely to succeed.

"If we are honest, we know that no external power is going to be able to force different religious communities or ethnic communities to co-exist for long," he said.


UN aid convoy destroyed in Syria

:: The Migration Crisis

"Until basic questions are answered about how communities co-exist, the embers of extremism will continue to burn. Countless human beings will suffer."

The US president said that although some countries were doing what they could to help with the refugee crisis, some wealthy countries could do more and leaders must have the empathy to imagine what it would be like if their families were forced to flee conflict.

Image: Syrian diplomats listen as Obama addresses the United Nations

Directing his words towards presidential hopeful Donald Trump, who has suggested a wall should be built along the US border with Mexico to control illegal immigration, Mr Obama said:

"The world is too small for us to simply be able to build a wall and prevent (extremism) from affecting our own societies."

In another apparent reference to Mr Trump, the US president criticised anger directed towards "innocent immigrants and Muslims".

The UN estimates there are about 21.3 million refugees forced to flee due to armed conflict or persecution.