Lance Cpl. Jeffery Webb, an infantryman with Weapons Company, 1st Battalion, 7th Marines, mans a security post during a mission in Helmand province, Afghanistan, on June 13. The notoriously violent Sangin district in Helmand was under siege by the Taliban and other insurgent fighters on Wednesday, coalition military officials said. (Photo by Cpl. Joseph Scanlan/ U.S. Marine Corps)

Well, that didn’t take long.

The last U.S. Marines pulled out of Afghanistan’s notoriously violent Sangin district last month, turning the security mission over to Afghan forces as part of the ongoing transition that requires all U.S. combat troops to be out of the country by year’s end. The question hanging over the Americans and the Afghans at the time: Would the Taliban or other insurgent groups in Sangin launch an assault to test the Afghan government, and when?

Now we know. The Taliban has waged a vicious onslaught in the district for four days, killing dozens of people while targeting military checkpoints, government buildings and other strategic locations, the Associated Press reported Wednesday. The AP reported there were some 800 enemy fighters in the region, while the Wall Street Journal put the number at about 1,000 — essentially the same size as a full battalion of Marines.

Coalition military officials in Kabul told Checkpoint that they provided various kinds of military support to Afghan National Security Forces over the last three days in northern Helmand province as a result, including helicopter support for medical evacuations, close-air support and intelligence, surveillance and reconnaissance assets.

“All checkpoints in Helmand are currently under ANSF control and this remains an ANSF-led operation,” one official said in an e-mail.

The violence may serve as an eye-opener for U.S. and Afghan officials, who have continued to proceed with the military drawdown in Afghanistan as the security crisis in Iraq dominates the news.

Sangin, in the northeast corner of Helmand province, has long been considered one of Afghanistan’s most violent regions. It was among the last areas that Marines in Helmand have withdrawn from as they prepare for the next phase of military operations after 2014. Dozens of coalition troops were killed there, and hundreds were maimed by improvised explosive devices and other booby traps. Fighting was said to have spread to nearby Kajaki and Now Zad districts by Wednesday.

The Taliban assault comes as Afghanistan copes with a political crisis  over alleged fraud in the June 14 run-off vote to choose a successor to President Hamid Karzai. Both candidates left in the running have pledged to sign an agreement that will keep some 9,800 U.S. troops in Afghanistan next year, but the corruption allegations have stalled the process.

The Taliban offensive also comes as three Marines were killed Monday in Helmand. They are Staff Sgt. David H. Stewart, 34; Lance Cpl. Brandon J. Garabrant, 19; and Lance Cpl. Adam F. Wolff, 25, Pentagon officials said. All three Marines were with 2nd Combat Engineer Battalion, of Camp Lejeune, N.C., and died while patrolling near Camp Leatherneck, the Marine Corps’ major base in Afghanistan, Commandant Gen. James Amos said Tuesday.

“It took the wind out of us. It was a rude awakening,” Amos said, according to The Hill. “There’s no question that the Taliban will probe and look for opportunity.”