"I think its a big country that has nuclear weapons that are able to be deployed. It has a real significant minority of radicalised population," Biden said.
Expressing concern over the law and order situation in the country, Biden said he is worried over its 'functional democracy'.
"Pakistan is not a completely functional democracy in the sense we think about it, and so that is my greatest concern," the US Vice-President said.
Biden's statement came in the wake of US military and intelligence chief report to the Congress about the existing vulnerabilities in the safety of Pakistan"s nuclear weapons, coupled with US long-standing concern over militant activities along the country's border areas.