A roadside bomb targeting police in rural northwestern Afghanistan killed at least nine members of an Afghan family and two policeman late on Monday, the Interior Ministry spokesman said on Tuesday.

The family members killed included two women and six children who were riding in police vehicles when the bomb exploded in Badghis province, the spokesman said in a statement said. Several people were wounded.

The attack occurred during the Muslim festival of Eid al-Adha.

This is yet another crime and atrocity by the Taliban against civilians on this special day of our celebration. They will never stop killing civilians, ministry spokesman Sediq Sediqqi said.

Police were helping the family of poor people by giving them a ride to the Qadis district's centre when the bomb exploded.

The Taliban did not immediately respond to queries on whether they were responsible.

The bomb came a day after seven civilians were killed and 15 wounded when a suicide bomber detonated explosives near a mosque in Baghlan province in the north of the country.

In a statement emailed on Friday, before the Eid holiday, the Taliban reiterated their threats against foreign troops but said insurgents should try to avoid killing civilians.

If it were irrefutably proven that the blood of innocent Muslims is spilt by ... negligence then their killer should be penalised according to Islamic law, the Taliban said.

Badghis province is one of the areas slated for a second handover of security responsibility from foreign to Afghan forces. It is in the hills of northwestern Afghanistan and shares a border with Turkmenistan.

Violence in the once-peaceful north has intensified with a series of high-profile attacks in the past year as insurgents seek to demonstrate their reach beyond their southern and eastern heartlands.

Despite the presence of more than 130,000 foreign soldiers, violence across Afghanistan is at its worst since the beginning of the U.S-led military campaign in 2001, according to the United Nations.

The NATO-led International Security Assistance Force says there has recently been a fall in the number of attacks by insurgents.

But the force's data excludes attacks that kill only civilians, and attacks on Afghan security forces operating without international troops.

(Reporting by Christine Kearney and Mirwais Haroooni, additional reporting by Sharafuddin Sharfyar, Writing by Christine Kearney, Editing by Robert Birsel)