Afghan President Hamid Karzai said violence in his country would not be ended by military means alone while Britain said it was considering sending more troops to Afghanistan because of heavy fighting.
Violence in Afghanistan is the worst it has been since the Taliban were ousted in 2001.
Hundreds of people have been killed in recent weeks and the US-led coalition said yesterday another member of its force had been killed.
A British soldier was shot dead in a clash on Wednesday, the sixth to die in four weeks.
Afghanistan says a resurgent Taliban would be impossible if the militants were not getting support in neighbouring Pakistan and key to ending the violence is ending that.
Karzai told an international conference in Tokyo that many Afghans were being killed by terrorists from outside Afghanistan.
While not mentioning Pakistan, he repeated a call for terrorism to be tackled at its roots.
"While there is currently a mighty struggle against terrorism going on in Afghanistan, this menace cannot be defeated by military means alone," Karzai said in a speech. His comments were released by his office in Kabul on Thursday.
"We must redouble our efforts on all dimensions of the war against terrorism, go after terrorists and their sources of training, inspiration and financing."
The United States also says the insurgents benefit from sanctuaries on the Pakistani side of the lawless border.
Pakistan, which used to back the Taliban, denies helping them but says small groups of militants are criss-crossing the border, where it too is fighting Taliban and Al-Qaeda-linked militants.
The Taliban have intensified attacks as a NATO peacekeeping mission prepares to take over from a separate US-led force in the country's south. The violence has taken both the government and its Western backers by surprise.
Most of the bloodshed has been in the south and east but four small bombs in Kabul killed one person and wounded nearly 50 this week.
Karzai said drug money was fuelling the violence. He also urged the international community to help build up the police in areas along the border with Pakistan. In some places, there was one policeman for every 1,500 people, he said.
The United States has 23,000 troops in Afghanistan, the most since its involvement began in 2001. The NATO force will soon have about 16,000.
But the violence has raised questions in NATO countries about a mission that looks set to have to do more fighting than peace-keeping.
NATO troops, most of them from Britain, Canada and the etherlands, will be moving into some of the country's most dangerous areas.
Britain, with 3,300 troops in the south who will soon be joining the NATO force, said it was considering sending more after requests from commanders in the field.
The US-led coalition has in recent weeks launched offensives in the south and east and a US spokesman said he expected violence to ease later in the year as a result of the offensives and the arrival of NATO forces.
"The Taliban has upped its operations because, obviously, with the arrival of NATO, they're at a critical point," the spokesman, Colonel Tom Collins, told a news conference.
"They have to make their move now."
The NATO force hopes to provide enough security for development to get going and to win over people who have yet to see aid in areas where the Taliban and drug gangs hold sway.
About 1,300 people have been killed in Afghanistan since January including 63 foreign troops.