US President Barack Obama yesterday called for the international community to step up aid for refugees.

"We have to open our hearts and do more to help refugees who are desperate for a home," he said in his final address to the UN General Assembly, adding that nations should stand by pledges of increased assistance "even when the politics are hard."

"We have to imagine what it would be like for our family, for our children. If the unspeakable happened to us," Obama said. "And we should all understand that ultimately our world will be more secure if we are prepared to help those in need and the nations who are carrying the largest burden with respect to accommodating these refugees."

Obama said all sides should welcome pledges of assistance that were made at the ongoing UN General Assembly meeting in New York.

Obama also insisted diplomacy is the only way to end the brutal five-year conflict in Syria, as a ceasefire brokered by Washington and Moscow lay in tatters.

Obama urged Israel to end occupation and Palestinians accept Israel. "Surely Israelis and Palestinians will be better off if Palestinians reject incitement and recognize the legitimacy of Israel ...(and if) Israel recognizes that it cannot permanently occupy and settle Palestinian land," he said.

Obama also said Russia was trying to recover "lost glory" through force.

He warned Russia that if it "continues to interfere in the affairs of its neighbors, it may be popular at home, it may fuel nationalist fervor for a time, but over time it is also going to diminish its stature and make its borders less secure."