Afghan President Hamid Karzai says attacks like the one on a luxury Kabul hotel that killed 11 people and wounded eight others will not deter the country's forces from taking over their security role as planned.

The five-hour highly coordinated siege of the Inter-Continental Hotel by heavily armed militants ended early Wednesday after all nine attackers either blew themselves up or were killed by Afghan and NATO forces.

The Taliban claimed responsibility for the attack, which began late Tuesday when the assailants penetrated the fortified hotel and set off several explosions. Those killed included Afghan hotel workers, police officers, and one Spanish guest.

President Karzai Wednesday condemned the attack on the landmark hotel as a “ruthless act of terror.” He praised the rapid response by security forces and said the attack will not stop the process of transferring security control from foreign to Afghan forces, which is due to begin in July.

U.S. President Barack Obama said Wednesday the Afghan capital is “much safer than it was and that Afghan forces are much more capable than they were.” He added the United States is “being successful” in its mission in Afghanistan and that it is in the U.S. national interest that Afghanistan “not collapse.”

The siege on the Inter-Continental came on the eve of a conference focused on Afghan preparations for the security handover. Several Afghan provincial officials taking part in the event were staying at the hotel.

The Inter-Continental was for years the Afghan capital's main hotel, and is frequented by foreigners. Afghan security officials say they are investigating how the militants were able to get past several security checkpoints to reach the hotel.

NATO helicopters helped end the five-hour stand-off after killing the last of the gunmen who were hiding on the hotel's roof. A NATO spokesman said coalition forces mobilized at the request of the Afghan Interior Ministry but the response was conducted primarily by the Afghan forces.

In other violence, NATO said one of its service members died in an insurgent attack in the south, while a combined Afghan-coalition force killed several insurgents during a security operation in southern Kandahar province.

Joint Afghan-NATO patrols also discovered several large weapons and drug caches in the south. All the drugs and weapons were safely destroyed by security forces.