Berlin - German Foreign Minister Frank-Walter Steinmeier left Thursday on a three-day visit to the United States during which he is due to confer with Secretary of State Condoleezza Rice.

Among the themes likely to come up for discussion in Washington on Friday are the Middle East conflict, Iran's nuclear programme and the situation in the Balkans.

On Wednesday, Steinmeier voiced concern about Iran's plans to expand the number of centrifuges at its uranium enrichment facility in Natranz.

The United Nations wants Iran to halt the process of uranium enrichment, which the US and other countries in the West fear is geared towards making a bomb.

Steinmeier and Rice last met at the NATO summit in Bucharest last week.

On Saturday, Steinmeier travels to Boston, where a project at the Massachusetts Institute of Technology (MIT) on combating climate change will be launched.

Also on Saturday, Steinmeier is to make a speech at Harvard University on a new transatlantic agenda.

During the trip, the German delegation intends to gain information at first hand on the foreign policy attitudes of the candidates in the US presidential election. (dpa)