Three suicide bombers targeted a government building in Afghanistan's southern province of Kandahar on Monday, injuring nine people, provincial governor Tooryali Weesa said.

"Three terrorists equipped with assault rifles and suicide vests targeted the department of National Security Directorate ( NSD) at 12:30 p.m. local time, wounding nine persons, including five members of same family, all civilians and four employees of NSD," Weesa told a news conference.

Going into details, he said that one of the attackers blew himself up next to the wall of the NSD department, which triggered one-hour war firefight during which another suicide bomber was shot dead and the third one was injured and then captured. "The injured suicide bomber's name is Najibullah," the governor added.

Earlier, another official Ahmad Wali Karzai, the head of provincial council said that one of the suicide bomber was killed when he exploded himself while two others were shot dead by security forces.

The official, furthermore, put the attacks on the enemies of peace, a reference against Taliban militants but the outfit has yet to make comment.

The attack on NSD building followed NATO's firing on a passenger bus earlier in the morning in Kandahar, which claimed the lives of four civilians and injured 18 others.

The situation in Kandahar, the birthplace of Taliban, has been deteriorating since emanating reports on military preparation to launch a major offensive against militants in their former stronghold Kandahar.

Afghan and NATO-led forces commanders said that the troops are getting ready to crackdown Taliban hideouts in Kandahar, possibly in June to ensure durable peace there.