Indian Mujahideen on Saturday claimed responsibility for the Delhi serial blasts.

In an e-mail sent to media houses, the outfit that had earlier also claimed responsibility for the Jaipur and Ahmedabad blasts, said, "Indian Mujahideen strikes back once more."

"Within 5 minutes from now... This time with the Message of Death, dreadfully terrorising you for your sins," the chilling note said.

"And thus our promise will be fulfilled. Inshallah," it read.

The outfit also threw a challenge to the security agencies, saying "Do whatever you want and stop us if you can," the mail which came from 'Arbi Hindi', with the e-mail ID of al_arbi_delhi@yahoo.com, said.