A car exploded in the eastern Afghan city of Jalalabad Wednesday, just hours before first lady Laura Bush (search) was due in the country.

The driver was killed but no one else was hurt. Investigators suspect the driver had been planning a suicide attack but the bomb detonated prematurely.

Jalalabad is about 80 miles from Kabul, where Mrs. Bush is to meet with Afghan President Hamid Karzai (search). She will also visit women's projects and dine with U.S. soldiers at Bagram Air Base.