KABUL, Afghanistan — A suicide bomber struck in Afghanistan’s eastern city of Jalalabad on Sunday, killing at least 19 people in the second attack in as many days targeting Taliban fighters, security forces and civilians celebrating a holiday cease-fire. The Taliban later rejected an extension of the cease-fire. Najibullah Kamawal, director of the provincial health department, said another 60 people were wounded in the attack, which struck a crowd of people as they left the governor’s compound. Saturday’s attack, which also took place in Jalalabad, killed at least 36 people and wounded 65, according to Kamawal, director of the provincial health department. No one has claimed the attacks, but they appeared to be the work of the Islamic State group, which is not included in the cease-fire and has clashed with the Taliban in the past.