NATO chief Jaap de Hoop Scheffer urged the UN and the European Union to beef up their role in Afghanistan, calling the mission there "the most important operation" for the Atlantic alliance.
In an interview published on Wednesday in the German daily Tagesspiegel, De Hoop Scheffer said NATO could help lay the groundwork for Afghanistan's long-term stability but the country needed more than military support.
"As NATO secretary general, I ensure that Afghanistan has a prominent place on NATO's radar screen," he said.
"But I believe that Afghanistan must be equally present on the radar screen of the European Union, the United Nations, the G8 and other international organisations," he added, referring to the Group of Eight industrialised nations.
He warned that neglect of Afghanistan would be a fatal mistake.
"If we do not reinforce our engagement in Afghanistan, Afghanistan will come to us. It will again become an exporter of terror. The consequences will be felt in Amsterdam or Berlin or London or New York."
The Dutchman said international organisations such as the EU and the UN could do more in areas such as fighting the drug trade, in particular by viewing the issue as a development problem.
"Do we have a real, internationally coordinated anti-drug strategy? I don't think so," he said.
"You cannot fight drugs simply by burning down poppy fields. Then the farmer asks himself, how can I feed my family?"
He said there was no need for "new and complicated structures" to organise international activities in Afghanistan, but added that better coordination was key.
"NATO cannot solve all the problems in Afghanistan on its own," he said.
"At the end of the day, the answer in Afghanistan cannot be a military one. The answer is nation-building and development."
NATO has faced a spike in violence in Afghanistan linked to the hardline Taliban movement, which the US-led coalition toppled from government in late 2001.
The alliance has appealed for member states to provide additional soldiers to bolster the 31,000 troops stationed in the country.
De Hoop Scheffer said NATO would be forced in the future to refine its concept of security, including expanding its operations to include protecting energy supplies.
"I could imagine that NATO with its naval forces could play a role in securing sea routes for oil and energy transports," he said.
"We are also talking about protecting critical infrastructure in the energy sector against terrorist threats."