And he warned that Taliban fighters had demonstrated "greater aggressiveness and more lethal tactics" in attacks over the past year and expressed concern that efforts to improve governance and development in the nation were being hampered by poor security in many areas and a lack of strong government control.

Nuclear concerns

Blair said global perceptions that the US had sparked much of the current global economic turmoil because of market excesses and inadequate regulation had increased criticism of the country's free market policies.

This in turn would hamper "long-time US objectives" such as the access to national capital markets and increasing domestic demand in Asia.

"It already has increased questioning of US stewardship of the global economy and the international financial structure," Blair said.

He also cautioned that while US intelligence could not be certain that Iran intended to develop nuclear weapons, the nation was "keeping open the option" to develop them.

On the issue of North Korea, Blair said the country is unlikely to use its nuclear weapons unless it feels its survival is at stake.