At least 50 people were killed and hundreds other injured in three separate bomb attacks in Kabul on Friday.

A wave of deadly attacks targeting the Afghan Police Academy and NATO base in Kabul killed at least 50 people and injured over 400 others, reported Tolo News. The Taliban group have claimed responsibility for the attacks.

The deadly bombings on Friday marked the deadliest attacks on Afghan capital in a single day, according to the Associated Press.

The first deadly bombing took place in Kabul's Shah Shaheed, in which a suicide truck bomb went off in a market early Friday, killing 15 civilians and injuring about 400 others. A suicide bomber, in the second bombing on same day, blew himself up neat the police academy in the Afghan capital on Friday evening, leaving at least 26 police trainees dead and 27 others injured, according to Khama Press.

Nine people, including an American soldier part of the NATO-led Resolute Support (RS) mission, were reportedly killed in third suicide attack in the Qasaba locality. "One Resolute Support servicemember and eight Resolute Support contracted civilians were killed during an attack on a coalition facility in Kabul, Afghanistan, August 7, 2015," NATO said in a statement, Khama Press reported.

The UN Assistance Mission in Afghanistan (UNAMA) said that Friday was the deadliest day for the Afghan capital in years.

"Those responsible for suicide and complex attacks in civilian-populated areas can no longer shrug off the disproportionate harm to the civilian population they cause," Nicholas Haysom, the Secretary-General's Special Representative for Afghanistan, said in a statement on Saturday.

"The Afghan people are resilient, but the suffering caused by these tactics in terms of civilian deaths, injuries, and the loss of family members, is extreme, irreversible and unjustifiable in any terms," Haysom said.