The United States is seeking to set "clear and achievable" goals for Afghanistan in a comprehensive strategy for which both Washington and its allies must take responsibility, Vice President Joe Biden said on Saturday.

This strategy should bring together U.S. civilian and military resources in order to prevent Afghanistan from becoming a safe haven for Islamist militants and help Afghans develop the capacity to secure their own future.

Speaking to a security conference, he also said that, "no strategy for Afghanistan can succeed without Pakistan.

"We must all strengthen our cooperation with the people and government of Pakistan, help them stabilise the Tribal Areas and promote economic development and opportunity throughout the country."