A roadside bomb planted by the Taliban killed a senior member of Afghanistan's peace council on Wednesday, officials said, the latest setback to efforts to end more than 11 years of war.

Shah Wali Khan, the head of the High Peace Council (HPC) in the key southern province of Helmand, died along with two police bodyguards when an explosion ripped through his vehicle.

The HPC is a government-appointed body set up in 2010 to open talks with the Taliban, but the insurgents refuse to negotiate with representatives of the US-backed President Hamid Karzai.

The Helmand provincial government said in a statement that Khan's convoy was travelling in Gereshk district as part of the handover of security from NATO-led troops to the Afghan security forces.

The Taliban "couldn't bear this beneficial step of our official envoy" and detonated the IED (improvised explosive device) under his vehicle, it added.

Taliban fighters have targeted HPC leaders in the past. In 2011 a suicide bomber with explosives hidden in his turban killed the council's chairman Burhanuddin Rabbani.

Any future peace talks face numerous hurdles, including confusion over who would represent the Taliban and Karzai's insistence that his appointees be at the centre of negotiations.

But the search for a political settlement has become a priority as the insurgency rages across south and east Afghanistan and as international combat troops prepare to withdraw by the end of next year.

Three British soldiers were killed in Helmand on Tuesday when their vehicle was hit by an IED on a routine patrol in the district of Nahr-e Saraj.

On Saturday the Taliban announced the start of their annual spring offensive, vowing a nationwide series of attacks as foreign troops pull back.

The Islamist militants broke off tentative contacts with the US in Qatar a year ago after the failure of attempts to agree on a prisoner exchange as a confidence-building measure.