U.S. Secretary of State Hillary Clinton canceled her trip to London and Turkey late Monday after her 92-year-old mother became ill.
Clinton was to have left Washington to join a regional meeting discussing various issues.
Earlier Monday, Secretary Clinton said Turkey must strengthen its democracy if it wants to realize its full potential, both economically and on the world stage.
Clinton told the American-Turkish Council in Washington that a vibrant Turkish economy depends on the free exchange of ideas and on the rule of law.
She said the United States hopes that the country's constitutional reform process results in a document that promotes respect for human rights including the right of people to worship freely and the right of minority groups to have a voice.
Clinton also said that Turkey must promote peace in its region if it is to be successful. She said the United States has been dismayed by the deterioration of relations between Turkey and Israel, and said the ties between them have served both countries well over the years.
She said tensions between Turkey and Cyprus are also a concern and voiced hope that Turkey would improve relations with Armenia.
However, Clinton said the United States is encouraged by signs of progress between Turkey and Greece and praised Turkey's condemnation of Syrian President Bashar al-Assad's violence against protestors.
Clinton said the United States welcomes Turkey's growing role in the region and said the country's economic leadership could be a key to modernizing economies across the Middle East and Northern Africa.
She said a strong U.S.-Turkey relationship has contributed to Turkey's prosperity in recent years, and said that economic growth will further the partnership between the two nations.