ANKARA, Turkey — Four people were killed and 12 wounded in Turkey on Tuesday, when suspected Kurdish rebels detonated a remote-controlled bomb on a bus carrying military personnel and their families.Istanbul Gov. Huseyin Avni Mutlu said two of the wounded were in critical condition following the early morning attack. The state-run Anatolia agency said the dead included the 17-year-old daughter of an officer.RELATED:De facto KurdistanKurdish rebels have repeatedly staged bomb attacks in Istanbul in the past but the last major bomb attack in the city was in 2007, when 17 people were killed.Kurdish rebels fighting for autonomy in the country's Kurdish-dominated southeast have dramatically stepped up their attacks on Turkish targets this month and had threatened to expand their war to cities in the west of the country.The roadside bomb went off on a usually quiet side road as the bus passed shortly after leaving a military housing complex, NTV television said.CNN-Turk television said there was no immediate claim of responsibility but that Kurdish rebels are believed to be behind the attack. The rebel group rarely claims credit for its attacks. Turkish troops killed seven Kurdish rebels in the country's north and southeast in two separate clashes overnight, the Anatolia agency said. The rebels have killed at least 13 soldiers in the region since Friday.