In a statement released by his spokeswoman, Annan said he is appalled by the brutal and callous bombing of trains in Mumbai, India.

He believed that "such acts serve only to reaffirm that terrorism constitutes one of the most serious threats to international peace and security, and to increase the urgency of coordinated action by all countries to defeat terrorism in all its forms and manifestations, committed by whomever, whenever, wherever and for whatever purpose."

The secretary-general also extended his deepest condolences to the government and people of India, and to all who have lost loved ones in this horrific slaughter.

According to Indian police and officials, at least 174 people were killed and more than 300 others injured when seven powerful bombs ripped through crowded commuter trains in Mumbai earlier Tuesday.