JERUSALEM -- An anti-tank missile fired from the Gaza Strip struck a school bus in southern Israel Thursday, wounding two people, including one child critically, Israeli officials said.
Israeli tanks quickly retaliated by opening fire across the border, killing a 50-year-old man and wounding seven other people, Palestinian medics said.
The sudden outbreak of violence illustrated the fragile situation along the Israel-Gaza border, where small bouts of violence can quickly escalate into heavy-scale warfare.
Israel's defense minister, Ehud Barak, ordered the army to respond quickly and said he held the Hamas militant group, which rules Gaza, responsible for the violence. There was no claim of responsibility for the attack.
Israeli medical services said the bus was nearly empty after dropping off school children and was carrying only the driver and a lone passenger at the time of the attack. Paramedics were trying to resuscitate a 16-year-old boy with a serious head wound at the scene. The driver was moderately wounded.
TV footage showed a yellow bus with its windows blown out and its rear charred. Police said it was struck by an anti-tank missile.
After a two-year lull, tensions have been rising between Israel and Palestinian militants in Gaza over the past few weeks.
Palestinian officials reported tank fire toward Gaza shortly after the missile attack. The Israeli fire killed a 50-year-old man and wounded seven people, said Palestinian health official Adham Abu Salmiya.
Israel usually responds with tough reprisals to Palestinian attacks. It also launched an airstrike on a Hamas training facility in northern Gaza.
The missile attack came hours after Israel carried out a series of airstrikes against tunnels it says are used by militants to smuggle weapons under the Egyptian border and carry out attacks.
Hamas and other Gaza militants have fired thousands of projectiles toward southern Israel in previous years. Israel launched a massive offensive in late 2008 to counter the near daily barrage.