Afghan and coalition forces Wednesday ended Kabul’s day-long insurgency, killing the remaining militants who attacked the U.S. Embassy and NATO, officials said.

The insurgents, in a brazen assault and standoff that began Tuesday afternoon, used rocket-propelled grenades and small arms fire, targeting the U.S. Embassy, NATO headquarters, and government and foreign organizations.

Though all of them were killed, the attacks once again showed the insurgents’ ability to break through the tightest security and infiltrate the capital.

The final operations ending the ordeal began early Wednesday with Afghan security forces, under air cover, focusing their attention on an under-construction multi-story building where the last of the insurgents were hiding and continuing their gunfight.

Siddiq Siddiqi, an Afghan Interior Ministry spokesman, said six militants were killed and the building was cleared by afternoon, CNN reported.

The BBC, quoting officials, said nine insurgents had been killed. Seven people, including four policemen, also were killed in the attacks, described as the most complex in the capital.

“Conditions in Kabul city are back to normal and all our countrymen can go about their daily lives without any worries,” an interior ministry spokesman was quoted by the BBC as saying.

The U.S. embassy said none of its staff members was among the casualties.

However, the BBC, quoting NATO, said six personnel from the International Security Assistance Force were injured.

While the Taliban claimed responsibility, Afghan officials blamed the Haqqani network for the attacks.

The U.S. Embassy in Kabul on its Web site has so far only confirmed the Tuesday incident, saying it included rocket-propelled grenade and small arms fire.

“Four Afghans were injured in the attack on the embassy compound, none with life threatening injuries,” an updated Embassy statement said. “They included three Afghan visa applicants and one local contract guard.”

The statement expressed appreciation “of the Afghan National Security Forces whose operations stopped the attack on the embassy compound.”

In Washington, State Department spokeswoman Victoria Nuland told reporters Tuesday it was too early to say who was behind the attacks.

“But as (Secretary of State Hillary Clinton) said this morning, these kinds of cowardly terrorist attacks are not going to stop our effort to help the Afghan people have the future that they want and that they deserve,” Nuland said.

Afghan authorities found explosives and burqas in a van at the building site and said the attackers were carrying hand grenades, pistols and an army knife, the BBC said. Elsewhere, the attackers’ suicide vests were found to contain ball-bearings.

The attacks came as U.S. and NATO forces are in the process of handing over the security of Kabul and other areas to Afghan forces under troop withdrawal plans to be completed by 2014.

The New York Times reported the insurgents were heavily armed and wore suicide vests.

The BBC reported the attackers in the multi-story building seemed to have been prepared for a long siege, having spent three days collecting needed weapons.

The New York Times said the attacks suggested the insurgents received support of people along the way.

CNN, which reported the attacks also injured 18 civilians, quoted a coalition officer as saying there had been intelligence the insurgents might launch a high-profile attack in Kabul around the 10th anniversary of the Sept. 11, 2001, terrorist attacks on the United States.

Separately, CNN quoted the Taliban as saying a suicide attacker targeted a police compound in the western part of Kabul but Afghan authorities said the attacker was shot before he entered the compound.

Another attacker set off a bomb in front of a high school, CNN quoted the interior ministry as saying, but it was not known how many casualties there were in the two incidents.

Afghan President Hamid Karzai condemned the attacks.

NATO Secretary-General Anders Fogh Rasmussen said the attacks were designed to derail the security handover.

“We are witnessing that the Taliban try to test (the) transition but they can’t stop it. Transition is on track and it will continue,” Rasmussen said.

U.S. Ambassador to Afghanistan Ryan Crocker said Wednesday about half a dozen rockets struck the embassy building. However, all of them were fired from afar and apparently did no damage, the BBC reported.

Crocker also said he believes the attacks were the work of the Haqqani network.

“If this is the best they can do, I find both their lack of ability and capacity and the ability of Afghan forces to respond to it actually encouraging in this whole transition process,” the BBC quoted him as saying.

Similar attacks in Kabul killed eight people last month at a British cultural center. Nine suicide bombers were involved in an attack on the Intercontinental Hotel in June.