President Barack Obama of the United States chose Cairo as the city from which to broadcast his historic appeal to the Muslim world on Thursday because Egypt is a "a strategic partner" of the U.S., according to an administration official.

Philip J. Crowley, the U.S. Assistant Secretary of State for Public Affairs, was defending the choice of Egypt in a State Department news briefing in Washington DC on Wednesday.

He had been asked by a journalist why Obama was issuing his appeal from a country ruled by "an authoritarian regime," instead of from "a populist Muslim country like Indonesia or Turkey, where democracy is flourishing."

Crowley responded that Egypt had been "a significant partner" in the search for peace in the Middle East ever since it signed a peace deal with Israel 30 years ago.

But he also said the decision to go to Egypt "is not to say that we don't have issues with Egypt."

He said whoever was responsible for a recent attack on the Egyptian dissident Ayman Nour "obviously... should be identified and brought to justice."

Agencies have reported that Nour accused elements within President Hosni Mubarak's ruling party of responsibility for the attack.

In Washington, Crowley said: "I do think that this... will be part of an ongoing dialogue that we have with... Egypt." He expected Secretary of State Hillary Clinton - who is in Egypt with Obama - would meet civil society groups while she was there.