U.S. Secretary of State Hillary Clinton on Thursday saw clear gaps between the six world powers and Iran over the latter's nuclear program as they wrapped up two- day talks in Baghdad, and urged the Islamic republic to "work to close the gaps."

"There are clearly gaps on what each side sees as possible and, you know, we think that the choice is now Iran's to work to close the gaps," the top U.S. diplomat told reporters after meeting with New Zealand Foreign Minister Murray McCully at the State Department.

"It's very clear that there is a lot of work still to do," she said.

She would not say much about the Baghdad talks, but stated that Washington would keep up the pressure on Tehran as it is pursuing a dual-track approach.

"As we lay the groundwork for these talks, we will keep up the pressure as part of our dual-track approach," she said. "All of our sanctions will remain in place and continue to move forward during this period."

The six world powers -- the United States, Britain, France, Russia, China and Germany, and Iran agreed to meet again in Moscow on June 18-19 for another round of talks to resolve their nuclear dispute.

European Union's foreign policy chief Catherine Ashton, who represented the six powers in the talks with Iran, said "Iran declared its readiness to address the issue of 20 percent enrichment" of uranium and came up with its own five-point plan in which recognition of Iran's right to enrichment is demanded.

In their Baghdad talks, the world powers sought to stop Iran from enriching weapons-grade uranium.

The Western countries suspect that Iran is developing nuclear bombs under the cover of its nuclear program, while Iran insists on the program's peaceful nature.