Republican presidential challenger Mitt Romney laid out some of his foreign policy goals Tuesday in a speech to global leaders meeting in New York.

Mr. Romney said he plans to initiate what he called “Prosperity Pacts” with developing nations. Under the plan, the U.S. government and private sector would identify barriers to investment and trade with developing countries. Countries that removed those barriers and opened their markets to American investment would receive U.S. aid.

The Republican presidential nominee said “an assistance program that helps unleash free enterprise creates enduring prosperity,” while a “temporary aid package” can only provide a “jolt” to an economy but not sustain it.

Mr. Romney spelled out the proposal at the Clinton Global Initiative forum, hosted by former U.S. president Bill Clinton.

Mr. Romney has fallen behind Democratic President Barack Obama in several voter opinion polls, both nationally and in several key states that will determine the eventual winner of the November 6 election.

Mr. Obama also addressed the conference, focusing on the need to fight “the outrage of human trafficking,” which he called “modern slavery.”

The U.S. president announced several new initiatives designed to combat the spread of human trafficking. He described the problem as a “debasement of our common humanity” that distorts economic markets, endangers public health and fuels violence.

Mr. Obama and Mr. Romney will take part in the first of three face-to-face debates on October 3.