NATO chief Jaap de Hoop Scheffer appealed Tuesday for more troops from outside the United States to be sent to Afghanistan to prevent it from again becoming a "safe haven" for terrorists. "No strategy will work if it is not matched by the right resources. I welcome (US president-elect Barack) Obama's commitment to boost troop levels but increased United States troop levels are not enough," he told a gathering of lawmakers from NATO member states in Valencia. "All of us, all the NATO allies, need to make greater efforts to the military, economic and civilian development (of Afghanistan)," the NATO secretary general said.