The UN Security Council on Monday condemned "in the strongest terms" a suicide truck bomb attack in the Afghan city of Kandahar, which reportedly killed five people, including three UN staff members.

The condemnation was contained in a statement read to the press here by Jog Ogwu, the Nigerian UN ambassador who holds the rotating Security Council presidency for November.

"The members of the Security Council reaffirm that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security and that any acts of terrorism are criminal and unjustifiable regardless of their motivation wherever, whenever, and by whomsoever committed," the statement said.

The attack took place at around 6 a.m. local time on Sunday, and resulted in the deaths of three UN security guards and two security contractors. Two other UN security guards were also wounded.

Earlier on Monday, UN Secretary-General Ban Ki-moon told a press conference here "Our thoughts this morning are with the victims and their families."

"As you may know a car bomb was exploded at the gate of a local NGO (non-governmental organization) that shares a common wall with the UNHCR compound," Ban said. "When the wall collapsed, suicide attackers entered the UN premises."

No group or individuals have yet to claim responsibility for the attacks so far, reports said.