The attack on Ghazni, a strategic centre on the main road linking the capital Kabul with southern Afghanistan, has come as a severe blow to President Ashraf Ghani.
A Yemeni health official and the International Committee of the Red Cross said than an air strike had hit the bus carrying children as it drove through a market in northern Saada province.
A Saudi-led coalition launched heavy air strikes on Yemen's main port city of Hodeidah on Friday, in an apparent resumption of military operations on the city after the Iranian-aligned Houthi movement attacked two Saudi oil tankers, residents said.
Unidentified air strikes have killed 12 civilians in a rebel-held pocket of southern Syria as regime ally Russia presses talks for Damascus to retake the area, a monitor said Wednesday.
Air strikes on Tuesday killed seven civilians in a sensitive southwestern province of Syria bordering the Israeli-occupied Golan Heights, a war monitor said.
Rebels controlling several towns in southern Syria were on Friday considering a deal for a regime takeover in exchange for an end to fierce bombing, state media and a monitor said.
Two Hamas security men were lightly hurt in one air strike in the southern Gaza Strip, residents said.
The United Nations delivered food and other vital aid supplies to the Yemeni port of Hodeidah on Wednesday even as a Saudi-led coalition carried out naval shelling and air strikes on the city, the top UN humanitarian official in Yemen told Reuters.
The death toll is expected to increase as some of the 60 injured in the strikes were in a critical condition, he said.
Air strikes killed at least 23 civilians including 10 children in a village held by the Islamic State group in northeastern Syria Tuesday, the Syrian Observatory for Human Rights monitor said.
Forty-two Palestinians have been killed by Israeli fire since March 30, according to the UN. Most of the Palestinians killed by Israel since the start of "March of Return" protests were shot by snipers on the border.