Carter has not confirmed the plans to meet Meshal but the Palestinian militant group has said the former Democratic president sent an envoy to Damascus, where the Hamas leader resides, requesting a meeting with the militant group's officials.
"I find it hard to understand what is going to be gained by having discussions with Hamas about peace when Hamas is, in fact, the impediment to peace," Rice said at a press event with German Foreign Minister Frank-Walter Steinmeier.
Rice was responding to a question about Carter's plans but did not mention him by name.
"Hamas is a terrorist organization," she said, repeating the Bush administration's explanation for why it will not meet with members of the group.
The State Department says it twice advised Carter against meeting any representative of Hamas. A Carter-Mashal meeting would be the first public contact in two years between a prominent American figure and Hamas officials.
A press release from the Carter Center said the former president was to lead a study mission to Israel, the West Bank, Egypt, Syria, Saudi Arabia and Jordan as part of his ongoing effort to support peace, democracy and human rights in the region.
Carter was awarded the Nobel Peace Prize in 2002 for his decades of work in mediating conflicts and his humanitarian travels for the Carter Center since he was in office. One of his mediations was the 1978 Camp David Accords between Egypt and Israel, for which Egypt's Anwar Sadat and Israel's Menachem Begin were awarded the 1978 Nobel Peace Prize.
Earlier Friday, Rice said the U.S. will consider fresh incentives and sanctions to persuade Iran to rein in its nuclear program but major changes in either are unlikely now.
"We will always continue to consider refreshing both tracks but this is not the time, I think, to expect major changes,"
Rice told reporters. "We have just passed a (UN) Security Council resolution (imposing additional sanctions) and we will see how Iran responds."
Report: Secret Iranian missile site revealed in new spy photos
A series of recently released spy photos have uncovered the secret location where Iran has allegedly been developing long-range ballistic missiles capable of striking Europe, The Times reported on Friday.
The satellite pictures pinpoint the facility where Iran launched its Kavoshgar 1 "research" rocket in February, according to the report. Iran has claimed that rocket was tested as part of its space program.
Analysis of the Digital Globe QuickBird satellite taken just days after the launch show details indicating that the site of the research rocket is the same location where Iran is preparing a ballistic missile with a range of 6,000 kilometers, the report said.
The site is located about 230 kilometers southeast of Tehran. The connection between the research rocket and Iran's long-range program was exposed by Jane's Intelligence Review following an analysis of the photos by a former Iraqi weapons inspector, said The Times.
Analysis of the photos suggest that Iran is pursuing a space program similar to that being developed in North Korea, with a focus on long-range missile technology, according to the report.
An analyst at the Institute of Technology, Geoffrey Forden, said that a structure on the Iranian site - roughly 40 meters in length - closely resembled a Taepodong long-range missile assembly facility in North Korea, The Times reported.
The editor of Janes's Proliferation has said that based on examination of the Iranian site, Tehran may be just five years away from developing the long-range missile, according to the report.