Taleban forces are retaking parts of Afghanistan as the post-war government shows signs of weakening, the UN's top peacekeeping official has said.
There are up to 400,000 militiamen in Afghanistan
In a regular briefing to the Security Council, Under Secretary General for Peacekeeping Operations Jean-Marie Guehenno said many causes of insecurity "remain unresolved".
"In several border districts (near Kandahar and Paktika), Taleban have been able to establish de facto control over district administration," he said.
Germany has agreed to send 450 troops to deploy around the northern city of Kunduz where President Hamid Karzai launched the Disarmament, Demobilisation and Reintegration Programme on Friday.
But so far no other countries have committed to the international force which the Security Council last week authorised to deploy outside the capital Kabul.
"There are worrying signs that the political compact that has
allowed the government to press ahead... in spite of the
differences of its individual members may be weakening," Mr Guehenno said.
"Insecurity has without question slowed the delivery of reconstruction, if not outright prevented it in the most insecure areas," he added.
The Afghan Government aims to disarm 100,000 militiamen within two years.
Estimates say they number 400,000 throughout the country.
However, there are still doubts whether Afghanistan's warlords will co-operate with the plan.
In Kunduz, Mr Karzai greeted about 1,000 fighters who had been disarmed over the past few days.
Mr Karzai called for a jihad for peace and reconstruction
He said all of Afghanistan must embark on a jihad (struggle) for peace and reconstruction.
Mr Karzai also paid tribute to the soldiers, saying they had suffered like all Afghans in 23 years of war
Arms for food
Fighters who take part in the UN-sponsored disarmament programme will, after handing over their weapons, receive some money, clothes and vouchers for food.
In the following weeks the disarmed militiamen will be interviewed and if jobs are available, employed.
However, the BBC's Crispin Thorold in Kunduz reports that critics believe it is unlikely warlords will be prepared to let their men fully participate in the programme.
Even if they do, the sceptics argue, the amount of artillery and the number of tanks at the disposal of the most powerful factions will make the scheme irrelevant.
Only small weapons are being collected at this stage.
The plan is being run under the auspices of the Afghan Ministry of Defence, led by Marshal Mohammed Fahim, who has one of Afghanistan's largest militias at his disposal.
In an effort to persuade others that the programme will be equitable, there have recently been reforms in the ministry in an attempt to reduce the influence of Marshal Fahim's faction.
Earlier in the week the commander of the international peacekeeping force, Isaf, called on the main militias in Kabul to remove tanks and heavy weapons from the city.
Demilitarisation of the capital was a key component of the Bonn Agreement, signed after the fall of the Taleban regime.
Reports on Friday from a commander of General Dostum of a deadly attack north of Kabul revealed how difficult the disarmament plan could be.
Ahmad Khan told the AP news agency that 10 people, including two
children, were killed when unknown attackers fired rockets and machine-guns at their truck in the town of Shamar in Samangan province.
He said the attackers probably suspected an important commander was riding in the truck.