MARJAH, Afghanistan – Marines and Afghan troops cleared the last major pocket of resistance in the former Taliban-ruled town of Marjah on Saturday — part of an offensive that is the run-up to a larger showdown this year in the most strategic part of Afghanistan’s dangerous south.

Although Marines say their work in Marjah isn’t done, Afghans are bracing for a bigger, more comprehensive assault in neighboring Kandahar province, the birthplace of the Taliban where officials are talking to aid organizations about how to handle up to 10,000 people who could be displaced by fighting.

”I was in Kabul, and we were talking that Kandahar will be next, but we don’t know when,” said Tooryalai Wesa, the governor of Kandahar. He’s begun working with international aid groups to make sure the next group of displaced Afghans have tents, water containers, medicine, food, blankets, lamps and stoves.

”Hopefully things will go smoothly, that people have learned lessons from the Marjah operation,” he said.

Shortages of food and medicine have been reported during the 2-week-old Marjah operation. The International Red Cross evacuated dozens of sick and injured civilians to clinics outside the area. The U.N. says more than 3,700 families, or an estimated 22,000 people, from Marjah and surrounding areas have registered in Helmand’s capital of Lashkar Gah 20 miles away.

Walid Akbar, a spokesman for the Afghan Red Crescent Society, said government aid was mostly received by those who made it to Lashkar Gah. Those stuck outside the city are getting little help, he said.

The Marjah offensive has been the war’s biggest combined operation since the 2001 U.S.-led invasion to topple the Taliban’s hard-line regime. It’s the first major test of NATO’s counterinsurgency strategy since President Obama ordered 30,000 new American troops to try to reverse Taliban gains.

The operation in Marjah is the tactical prelude to the bigger operation being planned for later in Kandahar, according to senior Obama administration officials. It was from in and around Kandahar that Taliban overlord Mullah Omar ruled Afghanistan before the Sept. 11 attacks in 2001. Bringing security to Kandahar city is a chief goal of NATO operations this year, according to the officials.