State Department spokesman Sean McCormack told a news conference on Tuesday that invitations had been sent to Israel and the Palestinian Authority, key Arab states, members of the Group of Eight leading industrialized nations, and international organizations including the World Bank and the International Monetary Fund.
However, many of the Arab countries have threatened to boycott the talks.
Egyptian President Hosni Mubarak met on Tuesday with Israeli Prime Minister Ehud Olmert to discuss preparations for the conference.
On November 26, representatives of the Quartet of international mediators on the Israeli-Palestinian conflict - the U.S., Russia, the United Nations and the European Union - are expected to hold a meeting chaired by U.S. Secretary of State Condoleezza Rice.
Arab nations are expected to reach a decision on whether to attend the U.S.-sponsored talks after ministerial-level negotiations in Cairo on Friday. Most of the countries believe Israel has not showed sufficient willingness to make progress on Palestinian statehood, which is the main goal of the conference.
The Palestinians want a detailed agreement specifying each party's commitment concerning key points, such as future borders, the status of Jerusalem, Palestinian refugees, and Israeli settlements, while the Israelis are looking for a more general guideline. Israel wants to retain control over East Jerusalem and key settlements in the West Bank as part of an eventual agreement.
Other invitees to the November 27 talks include Pakistan, India, Brazil, China, Turkey, along with several EU and southeast Asian nations.
