Obama takes case of 'broad coalition' to the U.N.

NEW YORK -- President Barack Obama takes his call for world cooperation against terror, climate change, Ebola and a host of other issues to the United Nations Wednesday, where he'll "lay out a broad vision of American leadership in a changing world," a White House official told CNN.

Obama will address the United Nations General Assembly amid numerous international crises, including the fight against ISIS in Syria and Iraq, lingering tensions in Ukraine and the spread of Ebola in Africa, which the U.S. Centers for Disease Control and Prevention recently said could infect as many as 1.4 million people by early next year.

"On all these issues, America acts not alone -- but leading large coalitions of countries, and he will call on more nations to join us," the official said of Obama's planned speech.

He will call on world leaders to join the coalition of nations fighting ISIS, which the U.S. government refers to as ISIL.

But he is also expected to "speak more comprehensively about the need to tackle the forces that give rise to ISIL -- extremist ideology, sectarian conflicts and the need for more affirmative alternatives to terror," according to the White House official.

Obama will later lead a special session of the U.N. Security Council focused on ISIS, which calls itself the "Islamic State." The group has seized portions of Syria and Iraq, prompting the United States and now some other nations to launch airstrikes against the terror organization.

The council is expected to consider a resolution requiring U.N. member states to take steps to make it more difficult for people to travel overseas to join ISIS, a growing problem for some European countries, particularly.