Kabul, Dec 26 (IANS): Two police officers were killed and three others injured on Saturday in separate explosions in Kabul, marking the latest in a series of bomb attacks in the Afghan capital city, the police confirmed

Two improvised explosive devices (IEDs) hit two Ranger-type police vehicles in Police District (PD) 3 and PD 6, destroying one and severely damaging the other during morning rush hour, Xinhua news agency quoted the police as saying in a statement.

The third was also an IED explosion which took place outside a traffic police stall in PD 8, causing no casualties but leaving destruction.

No group has claimed responsibility for the attack so far.

Saturday explosions come after a civilian and four employees of the country's main prison, including two female doctors, were killed and two other injured in an improvised bomb explosion in PD 7 on Tuesday.

On the same day, an army colonel and teacher of the Kabul military university was shot and killed by gunmen in PD 12.

In a report earlier this week, the Interior Ministry on Sunday claimed that 28 civilians were killed and 47 others injured in blasts across the country from December 17-20.

According to the Ministry, a total of 37 suicide attacks and 510 blasts have killed nearly 500 civilians and injured more than 1,050 others over the past three months in Afghanistan.

A total of 2,117 civilians had been killed and 3,822 injured from January 1 to September 30 this year, according to a report of the UN Assistance Mission in Afghanistan (UNAMA) released in October.