At least two Taliban militants are still hiding in the concrete skeleton of a building in Kabul, Afghanistan, eight hours after they fired bullets and rocket propelled grenades at the U.S. embassy.

Reports from the Afghan capital say that the insurgents are using hand grenades to keep local and NATO troops from getting too close, although security forces are said to have taken control of the first few floors of the 13-storey building.

The men reportedly hid weapons inside the high rise, which is under construction next to the American embassy, in preparation for the attack. The building is also being circled by NATO Black Hawks and National Air Force Mi35 helicopters.

Three militants were killed at the site earlier in the day, after they began shooting at the embassy. The attack was just one of a series of attacks in the capital that have left anywhere from two to 12 people dead, according to varying reports. The Taliban has claimed responsibility for Tuesday's events, which also includes attacks on NATO headquarters, a police station and three attempted suicide bombings at the Kabul airport.

The insurgency comes only two days after the tenth anniversary of Sept. 11, the tragic terrorist attack that directly lead to the United States' war in Afghanistan.

In June, President Barack Obama announced that 10,000 U.S. troops would be withdrawn from Afghanistan by the end of the year, and 30,000 more by 2012. All U.S. troops are scheduled to be out of the country by 2014, and security duties will be completely transferred to local police.

We are witnessing that the Taliban try to test transition but they can't stop it. Transition is on track and it will continue, Anders Fogh Rasmussen, the secretary general of NATO, commented.

The attacks cannot stop the [transition] process from taking place and cannot affect, but rather embolden our people's determination in taking the responsibility for their country's own affairs, President Karzai said in a statement.

On Saturday, two Afghan civilians were killed and 77 U.S. troops wounded when the Taliban detonated a truck bomb at the Combat Outpost Sayed Abad in Wardak province.

The Taliban has said that it will not stop fighting until all foreign troops are out of Afghanistan.

The type of multi-staged attacks seen on Tuesday is being used with increasing frequency in Afghanistan, as well as by insurgent groups all over the world. To maximize casualties, militants will detonate one explosive and then wait for police and emergency personnel to respond before detonating a second.

Insurgents have also shifted their focus from civilian to government targets, with hopes of destabilizing the state or scaring foreigners out of their country.