Operations against militants in Kabul ended on Wednesday and all the insurgents were killed, the Afghan Interior Ministry spokesperson Sediq Sediqi said.

The operation began on Tuesday and concluded at 8: 30 a.m. local time Wednesday. Totally 14 people had been killed, including six terrorists, four police and four civilians, said Sediqi.

He said 17 more people, including nine policemen and eight civilians, were injured.

"All the terrorists have been killed and the normalcy has returned," he added.

A group of militants occupied an under-construction building close to US embassy and the headquarters of NATO-led International Security Assistance Force (ISAF) Tuesday and began targeting the embassy, ISAF and government buildings around at 1:20 p.m. local time (0850 GMT), according to a Xinhua report.

Qari Yusuf Ahmadi, who said to speak for the Taliban outfit, claimed responsibility from unknown location an hour later.

He said a group of Taliban fighters equipped with arms and suicide vests targeted US embassy and NATO-led forces headquarters inflicting huge casualties.

Afghan President Hamid Karzai has termed the multiple attacks as coward terrorist act and strongly condemned it.

"The enemy does everything they can to affect the process of transition of security responsibilities of Afghan government. The attack cannot stop the process of transition but rather embolden our people's determination in taking over the security responsibility of their country," Karzai said in the statement released by his office.

The takeover from the over 140,000-strong NATO-led troops with nearly 100,000 of Americans, begun last July and is scheduled to be completed by the end of 2014.