CAPE TOWN, Feb. 21 (Xinhua) -- A group of unknown gunmen attacked a police station and killed five officers and an off-duty solider in Ngcobo, Eastern Cape Province, early Wednesday, police said.

The armed suspects entered the police station and randomly opened fire on the members on duty, killing three officers instantly, the South African Police Service (SAPS) said.

The suspects made off with a police van taking two other members, whose bodies were later found along the roadside with gunshot wounds, the SAPS said.

An off-duty soldier was also shot dead as the suspects were fleeing.

The attack drew immediate condemnation from National Commissioner of the SAPS, General Khehla John Sitole who called the killing "a heartless attack on the state."

"I am appalled and deeply saddened by the cold and callous attack on our colleagues this morning," said Sitole.

Sitole said he has activated a task team comprising experienced detectives of the SAPS and the Directorate for Priority Crime Investigation, known as the Hawks, to investigate this attack.

The motive for this attack is not clear yet, Sitole said.

Police have established that the suspects have robbed an ATM a short distance away from the police station and stolen 10 firearms as well as a police van.

This was believed to be the worst attack on the South African police in years, raising concern over growing risk to police officers amid rampant crimes.

Official statistics show that in the 2014/2015 financial year, 35 on-duty and 51 off-duty police officers were killed.