Security forces on the street where Afghanistan's top intelligence chief was attacked by a Taliban suicide bomber. Assadullah Khalid, was injured but is expected to recover.

President Hamid Karzai's paid a visit to the Kabul hospital where Khalid is being treated.

SOUNDBITE: AFGHAN PRESIDENT HAMID KARZAI SAYING:

"The head of our National directorate of security( Asadullah Khalid) is wounded in a cowardly terrorist attack, he is now undergoing surgery. Hospital Chief Mr. Nawabi has told me that National directorate of security chief is in a good condition and there is hope that he will recover and for further treatment he will be sent elsewhere for a better treatment."

For many, the fact that militants were able to carry out a successful attack on a key government official in the heart of the capital --- is a worrying sign.

The bombing seems to underscore Afghanistan's instability as well as its ability to handle its own security after NATO troops pull out of the region.