Iran's foreign minister says some of the 48 Iranians kidnapped by Syrian rebels are retired members of the Revolutionary Guards and the army and were in Damascus on a religious pilgrimage.

Wednesday, Iran's ISNA news agency quoted Foreign Minister Ali Akbar Salehi as denying that the Iranians have any current military connection.

The rebel Free Syrian Army describes those kidnapped Saturday as Revolutionary Guards on a “reconnaissance mission.”

Meanwhile, the opposition Syrian Observatory for Human Rights reported clashes in Aleppo Wednesday, which it described as the most violent since rebels claimed control of part of the city.

Rights group Amnesty International has released satellite images of Aleppo and the surrounding areas, showing what it says are signs of increased use of heavy weapons. The group says the images raise “urgent concerns” about an impending assault on the area. It also warns both rebels and government forces that attacks against civilians will be “clearly documented.”

Syrian President Bashar al-Assad has vowed to purge his country of what he called “terrorists.”

Jordan's King Abdullah says Mr. Assad could try to create a stronghold for his minority Alawite sect, if he is unable to keep control of the entire country. The king told U.S. broadcaster CBS that such an event would be a “worst case scenario” that creates decades of problems.

U.S. Secretary of State Hillary Clinton says it is time for world powers to begin planning for what will happen after Mr. Assad's government falls. She commented during a Tuesday appearance with South Africa's foreign minister in Pretoria.

“The intensity of the fighting in Aleppo, the defections, really point out how imperative it is that we come together and work toward a good transition plan.”

Clinton says she intends to discuss the issue with Turkish officials during her visit to Istanbul on Saturday.