Two British men and their Afghan driver and interpreter – all of whom work for a private security company – have been arrested in Kabul for carrying illegal weapons.

After more than 10 years of conflict and tens of thousands of lives lost, the international community has more responsibilities towards Afghanistan than ever. At the second multilateral conference in Bonn today, a decade on from the first, we must prove that those commitments will be comprehensively met.

Care agencies map out a future for Afghanistan to guide Bonn Conference foreign ministers tomorrow

More than 1,000 university students blocked a main highway in eastern Afghanistan yesterday after tribal elders agreed to discussions on a security pact that would allow American troops to remain in the country after a planned transfer of authority in 2014.

Nine members of the Afghan parliament are to lose their seats over allegations of election fraud.

When British troops pulled out of the capital of Afghanistan's southern Helmand province on 20 July, they did so with dignity. Afghans lined the streets of Lashkar Gah to present bouquets while the province's governor delivered a speech recalling how he had told the mother of a British soldier who was killed there that his death had not been vain.

Suicide bombers killed at least 19 people, 12 of them children, in an attack yesterday on government buildings in southern Afghanistan, the latest blow to a fragile region that has been destabilised by a string of assassinations.

Although he was dogged by allegations of corruption, Ahmed Wali Karzai, the younger half-brother of Afghanistan's president, Hamid, and head of the Kandahar Provincial Council, was the undisputed power broker in the southern region, the homeland of the Taliban and the focus of recent US-led campaigns to turn the tide against the insurgents. Karzai was shot dead by his long-time friend and head of security, Mohammed Sadar, who was himself killed by security forces.

The mayor of Kandahar has been killed by a suicide bomber, just two weeks after the Afghan president's half-brother was gunned down in the southern Taliban stronghold, officials said today.

Two Britons believed to be of Pakistani origin were being questioned in Helmand last night after being captured by the SAS in a raid in western Afghanistan. It is claimed that the two – a man and a woman – may have arrived in the country to carry out attacks against British targets on behalf of the Taliban.

Afghanistan began the long-publicised transition to control of its own security amid secrecy, not fanfare, on Sunday, a reminder of how volatile the country is even as Nato troop drawdowns get under way.

President Hamid Karzai buried his brother in a shrine at their ancestral home of Karz yesterday, leading an outpouring of grief for one of the country's most controversial politicians.