Three people have been killed and at least six others wounded in a suspected roadside bomb attack on a bus carrying soldiers in Istanbul, Turkey, according to BBC.

The explosion took place when the vehicle was passing through the Halkali district on the outskirts of the city.

No-one has yet said they carried out the attack.

It comes as Kurdish rebel group, the PKK, has stepped up its attacks on Turkish military targets, killing more than 50 soldiers over the past months.

A convoy of three buses had just left a military residential compound in the Istanbul suburb when a roadside explosion hit the last bus, killing two soldiers and an 18-year-old girl, reports the BBC`s Jonathan Head in Istanbul.

A number of seriously injured survivors were taken to hospital.

Government review

The local governor has described the blast as a bomb attack, although he says it is not clear yet who has carried it out.

The suspicion is bound to fall on the separatist Kurdistan Workers` Party (PKK), our correspondent says, which has staged a number of bold attacks on military targets in recent weeks, killing 11 soldiers over the weekend.

The government says it is now reviewing how it confronts the PKK. There has been criticism of the use of inexperienced recruits in frontline positions along the Iraqi border, our correspondent adds.

Last month, the PKK announced it had given up all hopes of dialogue with the government and said it would increase armed operations in all regions of Turkey.