Hours after Prime Minister Manmohan Singh expressed concern over Pakistan's will to punish those responsible for the terrorist attacks in Mumbai, President Barack Obama asked Islamabad to move against the perpetrators.

A couple of hours after meeting Manmohan Singh, Obama on Sunday told Pakistani Prime Minister Yusuf Raza Gilani that the Indian leader was sincere in improving ties with Islamabad, but wants Pakistan to take action against those responsible for the Mumbai attacks.