At least 17 people including women and children have been killed by a roadside bomb in in western Afghanistan, officials have told the BBC.

Ten of the dead were members of the same family, police said.

Police told the AP news agency that the bomb in Herat province had been placed near a trailer being pulled by a motorcycle to transport civilians.

They said the Taliban had apparently planted the bomb in an attempt to kill Afghan troops.

Instead, the device went off next to the makeshift vehicle.

Police say that those killed were travelling from their village in Obe district to a local town when it hit the improvised explosive device (IED).

Twelve of the dead were women and four were children, officials said.

The attack is being blamed on the Taliban, who are yet to comment on the bombing.

IEDs have increasingly been used by the Taliban over the past two years in Afghanistan and have killed hundreds of people.

The BBC's Bilal Sarwary in Kabul says that in addition they have stifled the economy and created a climate of fear - and their capacity to wreak destruction and havoc appears to be increasing.

Our correspondent says the exact number of people killed by such bombs is difficult to calculate, but officials say they were behind the deaths of most of the of 1,800 police and 900 army personnel killed last year.

Ten civilians including eight women were killed in a similar attack in the southern province of Kandahar last week.

In consecutive weeks in November, at least 37 people were killed in separate roadside bombings of wedding parties.