US Vice-President Joe Biden appealed to NATO allies yesterday to help the United States tackle worsening security in Afghanistan, saying the alliance was struggling to deal with a threat to the West as a whole.

"The deteriorating situation in the region poses a security threat not just to the United States but to every single nation round this table," Biden told representatives of the 26-country military pact during a visit to Brussels.

"We are not now winning the war, but the war is far from lost," he told a news conference after three hours of talks.