Afghan forces have formally taken over security for the whole of the country from NATO-led troops, completing a process begun in 2011, BBC News reported.

President Hamid Karzai announced the move at a ceremony during which NATO forces handed over control for the last 95 districts.

The event marks a significant milestone since U.S.-led forces ousted the Taliban following the 9/11 attacks of 2001.

Ahead of the event, a suicide bomber killed three people in Kabul.

The attacker is believed to have targeted the convoy of Haji Mohammad Mohaqeq, an MP and a leader of the Hazara ethnic minority. Mohaqeq escaped with minor injuries.

Both President Karzai and NATO chief Anders Fogh Rasmussen described as historic the ceremony marking the handover of security responsibility.

"Our security and defense forces will now be in the lead," President Karzai said in a speech. "From here, all security responsibility and all security leadership will be taken by our brave forces."

This is the first time since the withdrawal of Soviet forces in 1989 that security across the country has become the responsibility of forces led by the Afghan government.