Hamas says it has brokered a deal for Gazas groups to stop firing on Israel, after another day of violent exchanges. Hamas, which governs Gaza, said the truce was designed to stop an escalation of Israeli aggression. The militant wing of Hamas earlier hit an Israeli bus with an anti-tank shell, injuring two people. Israeli forces replied with air strikes and tank fire, killing four and wounding 30, Palestinian doctors say. The bus attack was condemned by the US, which said it was particularly concerned by reports that the Gaza militants had used an advanced anti-tank weapon to target civilians. The bus had been dropping off schoolchildren near the Nahal Oz kibbutz, and was carrying only one passenger when it was hit, Israeli medical sources said. A 16-year-old boy suffered a serious head wound and was taken to hospital for surgery.