KHOST: A bomb planted on the side of a road killed newborn twins, their mother and grandmother in southeastern Afghanistan on Sunday, while gunmen on a motorbike shot dead a school principal, police said. The bomb struck the family while they were in a wagon driving home from a clinic in Khost, where the babies were born overnight, deputy police chief Sakhi Mir said. “Two newborn babies and two women were martyred in the roadside bomb blast and another woman and a man in the vehicle were wounded,” Mir said. In Helmand earlier on Sunday, armed men on motorbikes killed a school principal as he left a mosque, provincial education director Saiful Malok Nuri said.