Turkish officials say a remote-controlled roadside bomb in the city of Istanbul has blasted a bus carrying soldiers and their families, killing five people, and wounding 12 others. The attack comes as fighting escalates between the PKK and the Turkish state. The bombing raised the number of Turkish soldiers killed in rebel attacks since Friday to 17. Police blame the attack on the autonomy-seeking Kurdish rebel group the Kurdistan Workers Party or PKK. Provincial governor Huseyin Avni Mutlu said the attack was an act of terrorism. The Kurdistan Freedom Falcons, an offshoot of the PKK, claimed responsibility for the attack.