WASHINGTON: Pakistan's government has abdicated to the Taliban in agreeing to impose Islamic law in the Swat valley and the country now poses a "mortal threat" to the world, US Secretary of State Hillary Clinton said on Wednesday.

Surging violence across Pakistan and the spread of Taliban influence through its northwest are reviving concerns about the stability of the nuclear-armed country, an important US ally vital to efforts to stabilize neighboring Afghanistan.

US President Barack Obama, who on March 27 unveiled a new strategy that seeks to crush Al-Qaida and Taliban militants in Afghanistan and those operating from across the border in Pakistan, meets the presidents of both countries May 6-7.