KABUL - A bomb has blown up a bus in Afghanistan killing at least 11 people and wounding dozens, officials said on Monday, the latest in a series of deadly blasts that has come as foreign forces withdraw.The roadside bomb exploded late on Sunday in the southern province of Zabul, the provincial governor's spokesman, Gul Islam Sial, said. Woman and children were among the wounded, he said. An interior ministry spokesman said 28 people were wounded.There was no immediate claim of responsibility. Taliban insurgents did not immediately respond to a request for comment.Early on Monday, a blast hit a minibus in Parwan province, just north of the capital, Kabul, killing two people and wounding nine, the Interior Ministry said.Violence has been rising sharply in recent weeks after the United States announced it would withdraw all of its troops by Sept. 11, 20 years after al Qaeda attacks on the United States triggered U.S.-led intervention in Afghanistan.The Taliban announced late on Sunday they would declare a three-day ceasefire for the religious holiday of Eid al-Fitr later this week.The ceasefire declaration came two days after bombings outside a school in Kabul killed 68 people, most of them girl students, and injured more than 165 people.At least 11 people were killed and dozens injured in the bombing of a bus in Afghanistan's southern Zabul province, officials said on Monday.The blast took place late on Sunday night, said Zabul's provincial governor's spokesman Gul Islam Sial, adding 25 people were injured including women and children who were in critical condition.Violence in the country has been rising sharply in recent weeks after the United States announced it would withdraw troops by Sept. 11. The insurgent Taliban announced late on Sunday they would declare a three-day ceasefire for the religious holiday of Eid-ul-Fitr later this week.