The United States could come under a nuclear threat from South Asia in 20 years and a likely source of Islamic terrorism could be from Pakistan that has slipped into political chaos, a top official of a think tank in Washington has warned.

Pak a partner in war on terror: US

"A likely source of Islamic terrorism directed against the United States could come from a Pakistan that itself slipped into political chaos or a Bangladesh that seems to be unsure of its identity," Stephen Cohen, Director of the South Asia Project at the Brookings Institution, a liberal think tank, warned a House Armed Services Committee panel on Wednesday.

"If Pakistan does not cohere as a modern, more or less centrist state, if the army loses its grip, and if regional separatist and radical Islamists grow in influence, Pakistan could become a grave threat to the United States and its neighbours, including Iran, China, Afghanistan and India," he said.

$82 billion more for war on terror

Cohen claimed that the growing South Asian technical and military capabilities could extend Indian or Pakistani power to other regions where important US interests, investments or base facilities lay.

Over a 20-year period, the US itself could come within range of South Asian nuclear capabilities, he warned, recommending increased military cooperation and exchanges with South Asian countries as well as cultural exchanges to "deepen mutual understanding."

US budget focuses on war on terror

He suggested that Islamic terrorists pose a threat not only to the US but also to Chinese interests in the region, and urged for greater cooperation between US and China on counter-terrorism efforts.