Massoud Hossaini/AFP/Getty Images

Insurgents launched one of their most coordinated attacks in Kabul today, piercing the city’s most secure area to fire rocket-propelled grenades and automatic weapons at the U.S. Embassy and the adjoining NATO military headquarters.

The assault was timed to coincide with at least three other suicide bomb attacks in the city, a sign that despite U.S. claims of progress in Afghanistan, militants are still able to launch high-profile — if not always successful — attacks in the capital.

Today’s attack began at 1:30 p.m. and was still continuing at 9:00 p.m., a seven-and-a-half-hour siege that killed at least six and wounded 18. It is the third major attack in Kabul in the last two-and-a-half months, one of the most violent periods in the last few years and a challenge to Afghan forces, who are responsible for but have been unable to guarantee security in Kabul.

The insurgents took over a construction site less than 1,000 feet from the embassy and fought off not only Afghan police and commandos on the ground but also Afghan commandos who arrived in Soviet-made Afghan helicopters.

Insurgents fired at the embassy and military base, but there were no injuries caused in either location, a sign that their shooting was wild and, perhaps, random.

One of those killed was an Afghan who lived in a nearby house that was hit by a rocket.

Before the embassy attack began, at least three suicide bombers in different parts of the city targeted police, according to the city’s police chief, Gen. Ayuob Salangi. The worst of the attacks occurred in west Kabul, about five miles from the embassy, where a suicide attacker tried to enter a police precinct and blew himself up as he was shot, killing one policeman and injuring three others.