One of the suspected planners of last month's attack by gunmen in Mumbai was arrested by Pakistani security forces in a raid on a militant camp near Muzaffarabad, sources in the capital of Pakistani Kashmir said yesterday.

The Pakistani government has so far been silent over Sunday's raid at the camp used by Lashkar-e-Taiba fighters in the hills outside Muzaffarabad.

India and the United States have pressed Pakistan to act against militants suspected of being behind the attacks, which killed at least 171 people, or risk an escalation in tensions between the nuclear-armed neighbors.